diff --git a/src/main/java/stirling/software/SPDF/controller/api/RearrangePagesPDFController.java b/src/main/java/stirling/software/SPDF/controller/api/RearrangePagesPDFController.java
index 718f8520..8ae1b533 100644
--- a/src/main/java/stirling/software/SPDF/controller/api/RearrangePagesPDFController.java
+++ b/src/main/java/stirling/software/SPDF/controller/api/RearrangePagesPDFController.java
@@ -6,6 +6,11 @@ import stirling.software.SPDF.utils.WebResponseUtils;
 
 import java.util.ArrayList;
 import java.util.List;
+import javax.script.ScriptEngineManager;
+import javax.script.ScriptEngine;
+import javax.script.ScriptException;
+
+import javax.script.ScriptEngine;
 
 import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.pdmodel.PDPage;
@@ -24,228 +29,241 @@ import io.swagger.v3.oas.annotations.Parameter;
 @RestController
 public class RearrangePagesPDFController {
 
-    private static final Logger logger = LoggerFactory.getLogger(RearrangePagesPDFController.class);
+	private static final Logger logger = LoggerFactory.getLogger(RearrangePagesPDFController.class);
 
+	@PostMapping(consumes = "multipart/form-data", value = "/remove-pages")
+	@Operation(summary = "Remove pages from a PDF file", description = "This endpoint removes specified pages from a given PDF file. Users can provide a comma-separated list of page numbers or ranges to delete.")
+	public ResponseEntity<byte[]> deletePages(
+			@RequestPart(required = true, value = "fileInput") @Parameter(description = "The input PDF file from which pages will be removed") MultipartFile pdfFile,
+			@RequestParam("pagesToDelete") @Parameter(description = "Comma-separated list of pages or page ranges to delete, e.g., '1,3,5-8'") String pagesToDelete)
+			throws IOException {
 
-    @PostMapping(consumes = "multipart/form-data", value = "/remove-pages")
-    @Operation(summary = "Remove pages from a PDF file",
-            description = "This endpoint removes specified pages from a given PDF file. Users can provide a comma-separated list of page numbers or ranges to delete.")
-    public ResponseEntity<byte[]> deletePages(
-            @RequestPart(required = true, value = "fileInput")
-            @Parameter(description = "The input PDF file from which pages will be removed")
-                    MultipartFile pdfFile,
-            @RequestParam("pagesToDelete")
-            @Parameter(description = "Comma-separated list of pages or page ranges to delete, e.g., '1,3,5-8'")
-                    String pagesToDelete) throws IOException {
+		PDDocument document = PDDocument.load(pdfFile.getBytes());
 
-        PDDocument document = PDDocument.load(pdfFile.getBytes());
+		// Split the page order string into an array of page numbers or range of numbers
+		String[] pageOrderArr = pagesToDelete.split(",");
 
-        // Split the page order string into an array of page numbers or range of numbers
-        String[] pageOrderArr = pagesToDelete.split(",");
+		List<Integer> pagesToRemove = pageOrderToString(pageOrderArr, document.getNumberOfPages());
 
-        List<Integer> pagesToRemove = pageOrderToString(pageOrderArr, document.getNumberOfPages());
+		for (int i = pagesToRemove.size() - 1; i >= 0; i--) {
+			int pageIndex = pagesToRemove.get(i);
+			document.removePage(pageIndex);
+		}
+		return WebResponseUtils.pdfDocToWebResponse(document,
+				pdfFile.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_removed_pages.pdf");
 
-        for (int i = pagesToRemove.size() - 1; i >= 0; i--) {
-            int pageIndex = pagesToRemove.get(i);
-            document.removePage(pageIndex);
-        }
-        return WebResponseUtils.pdfDocToWebResponse(document, pdfFile.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_removed_pages.pdf");
+	}
 
-    }
+	private enum CustomMode {
+		REVERSE_ORDER, DUPLEX_SORT, BOOKLET_SORT, ODD_EVEN_SPLIT, REMOVE_FIRST, REMOVE_LAST, REMOVE_FIRST_AND_LAST,
+	}
 
-    private List<Integer> pageOrderToString(String[] pageOrderArr, int totalPages) {
-        List<Integer> newPageOrder = new ArrayList<>();
-        // loop through the page order array
-        for (String element : pageOrderArr) {
-            // check if the element contains a range of pages
-            if (element.contains("-")) {
-                // split the range into start and end page
-                String[] range = element.split("-");
-                int start = Integer.parseInt(range[0]);
-                int end = Integer.parseInt(range[1]);
-                // check if the end page is greater than total pages
-                if (end > totalPages) {
-                    end = totalPages;
-                }
-                // loop through the range of pages
-                for (int j = start; j <= end; j++) {
-                    // print the current index
-                    newPageOrder.add(j - 1);
-                }
-            } else {
-                // if the element is a single page
-                newPageOrder.add(Integer.parseInt(element) - 1);
-            }
-        }
+	private List<Integer> removeFirst(int totalPages) {
+		if (totalPages <= 1)
+			return new ArrayList<>();
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = 2; i <= totalPages; i++) {
+			newPageOrder.add(i - 1);
+		}
+		return newPageOrder;
+	}
 
-        return newPageOrder;
-    }
+	private List<Integer> removeLast(int totalPages) {
+		if (totalPages <= 1)
+			return new ArrayList<>();
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = 1; i < totalPages; i++) {
+			newPageOrder.add(i - 1);
+		}
+		return newPageOrder;
+	}
 
-    private enum CustomMode {
-        REVERSE_ORDER,
-        DUPLEX_SORT,
-        BOOKLET_SORT,
-        ODD_EVEN_SPLIT,
-        REMOVE_FIRST,
-        REMOVE_LAST,
-        REMOVE_FIRST_AND_LAST,
-    }
+	private List<Integer> removeFirstAndLast(int totalPages) {
+		if (totalPages <= 2)
+			return new ArrayList<>();
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = 2; i < totalPages; i++) {
+			newPageOrder.add(i - 1);
+		}
+		return newPageOrder;
+	}
 
-    private List<Integer> removeFirst(int totalPages) {
-        if (totalPages <= 1) return new ArrayList<>();
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = 2; i <= totalPages; i++) {
-            newPageOrder.add(i - 1);
-        }
-        return newPageOrder;
-    }
+	private List<Integer> reverseOrder(int totalPages) {
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = totalPages; i >= 1; i--) {
+			newPageOrder.add(i - 1);
+		}
+		return newPageOrder;
+	}
 
-    private List<Integer> removeLast(int totalPages) {
-        if (totalPages <= 1) return new ArrayList<>();
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = 1; i < totalPages; i++) {
-            newPageOrder.add(i - 1);
-        }
-        return newPageOrder;
-    }
+	private List<Integer> duplexSort(int totalPages) {
+		List<Integer> newPageOrder = new ArrayList<>();
+		int half = (totalPages + 1) / 2; // This ensures proper behavior with odd numbers of pages
+		for (int i = 1; i <= half; i++) {
+			newPageOrder.add(i - 1);
+			if (i <= totalPages - half) { // Avoid going out of bounds
+				newPageOrder.add(totalPages - i);
+			}
+		}
+		return newPageOrder;
+	}
 
-    private List<Integer> removeFirstAndLast(int totalPages) {
-        if (totalPages <= 2) return new ArrayList<>();
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = 2; i < totalPages; i++) {
-            newPageOrder.add(i - 1);
-        }
-        return newPageOrder;
-    }
+	private List<Integer> bookletSort(int totalPages) {
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = 0; i < totalPages / 2; i++) {
+			newPageOrder.add(i);
+			newPageOrder.add(totalPages - i - 1);
+		}
+		return newPageOrder;
+	}
 
-    
-    private List<Integer> reverseOrder(int totalPages) {
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = totalPages; i >= 1; i--) {
-            newPageOrder.add(i - 1);
-        }
-        return newPageOrder;
-    }
+	private List<Integer> oddEvenSplit(int totalPages) {
+		List<Integer> newPageOrder = new ArrayList<>();
+		for (int i = 1; i <= totalPages; i += 2) {
+			newPageOrder.add(i - 1);
+		}
+		for (int i = 2; i <= totalPages; i += 2) {
+			newPageOrder.add(i - 1);
+		}
+		return newPageOrder;
+	}
 
-    private List<Integer> duplexSort(int totalPages) {
-        List<Integer> newPageOrder = new ArrayList<>();
-        int half = (totalPages + 1) / 2; // This ensures proper behavior with odd numbers of pages
-        for (int i = 1; i <= half; i++) {
-            newPageOrder.add(i - 1);
-            if (i <= totalPages - half) { // Avoid going out of bounds
-                newPageOrder.add(totalPages - i);
-            }
-        }
-        return newPageOrder;
-    }
+	private List<Integer> processCustomMode(String customMode, int totalPages) {
+		try {
+			CustomMode mode = CustomMode.valueOf(customMode.toUpperCase());
+			switch (mode) {
+			case REVERSE_ORDER:
+				return reverseOrder(totalPages);
+			case DUPLEX_SORT:
+				return duplexSort(totalPages);
+			case BOOKLET_SORT:
+				return bookletSort(totalPages);
+			case ODD_EVEN_SPLIT:
+				return oddEvenSplit(totalPages);
+			case REMOVE_FIRST:
+				return removeFirst(totalPages);
+			case REMOVE_LAST:
+				return removeLast(totalPages);
+			case REMOVE_FIRST_AND_LAST:
+				return removeFirstAndLast(totalPages);
+			default:
+				throw new IllegalArgumentException("Unsupported custom mode");
+			}
+		} catch (IllegalArgumentException e) {
+			logger.error("Unsupported custom mode", e);
+			return null;
+		}
+	}
 
+	@PostMapping(consumes = "multipart/form-data", value = "/rearrange-pages")
+	@Operation(summary = "Rearrange pages in a PDF file", description = "This endpoint rearranges pages in a given PDF file based on the specified page order or custom mode. Users can provide a page order as a comma-separated list of page numbers or page ranges, or a custom mode.")
+	public ResponseEntity<byte[]> rearrangePages(
+			@RequestPart(required = true, value = "fileInput") @Parameter(description = "The input PDF file to rearrange pages") MultipartFile pdfFile,
+			@RequestParam(required = false, value = "pageOrder") @Parameter(description = "The new page order as a comma-separated list of page numbers, page ranges (e.g., '1,3,5-7'), or functions in the format 'an+b' where 'a' is the multiplier of the page number 'n', and 'b' is a constant (e.g., '2n+1', '3n', '6n-5')") String pageOrder,
+			@RequestParam(required = false, value = "customMode") @Parameter(schema = @Schema(implementation = CustomMode.class, description = "The custom mode for page rearrangement. "
+					+ "Valid values are:\n" + "REVERSE_ORDER: Reverses the order of all pages.\n"
+					+ "DUPLEX_SORT: Sorts pages as if all fronts were scanned then all backs in reverse (1, n, 2, n-1, ...). "
+					+ "BOOKLET_SORT: Arranges pages for booklet printing (last, first, second, second last, ...).\n"
+					+ "ODD_EVEN_SPLIT: Splits and arranges pages into odd and even numbered pages.\n"
+					+ "REMOVE_FIRST: Removes the first page.\n" + "REMOVE_LAST: Removes the last page.\n"
+					+ "REMOVE_FIRST_AND_LAST: Removes both the first and the last pages.\n")) String customMode) {
+		try {
+			// Load the input PDF
+			PDDocument document = PDDocument.load(pdfFile.getInputStream());
 
-    private List<Integer> bookletSort(int totalPages) {
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = 0; i < totalPages / 2; i++) {
-            newPageOrder.add(i);
-            newPageOrder.add(totalPages - i - 1);
-        }
-        return newPageOrder;
-    }
+			// Split the page order string into an array of page numbers or range of numbers
+			String[] pageOrderArr = pageOrder != null ? pageOrder.split(",") : new String[0];
+			int totalPages = document.getNumberOfPages();
+			System.out.println("pageOrder=" + pageOrder);
+			System.out.println("customMode length =" + customMode.length());
+			List<Integer> newPageOrder;
+			if (customMode != null && customMode.length() > 0) {
+				newPageOrder = processCustomMode(customMode, totalPages);
+			} else {
+				newPageOrder = pageOrderToString(pageOrderArr, totalPages);
+			}
 
-    private List<Integer> oddEvenSplit(int totalPages) {
-        List<Integer> newPageOrder = new ArrayList<>();
-        for (int i = 1; i <= totalPages; i += 2) {
-            newPageOrder.add(i - 1);
-        }
-        for (int i = 2; i <= totalPages; i += 2) {
-            newPageOrder.add(i - 1);
-        }
-        return newPageOrder;
-    }
+			// Create a new list to hold the pages in the new order
+			List<PDPage> newPages = new ArrayList<>();
+			for (int i = 0; i < newPageOrder.size(); i++) {
+				newPages.add(document.getPage(newPageOrder.get(i)));
+			}
 
-    private List<Integer> processCustomMode(String customMode, int totalPages) {
-        try {
-            CustomMode mode = CustomMode.valueOf(customMode.toUpperCase());
-            switch (mode) {
-                case REVERSE_ORDER:
-                    return reverseOrder(totalPages);
-                case DUPLEX_SORT:
-                    return duplexSort(totalPages);
-                case BOOKLET_SORT:
-                    return bookletSort(totalPages);
-                case ODD_EVEN_SPLIT:
-                    return oddEvenSplit(totalPages);
-                case REMOVE_FIRST:
-                    return removeFirst(totalPages);
-                case REMOVE_LAST:
-                    return removeLast(totalPages);
-                case REMOVE_FIRST_AND_LAST:
-                    return removeFirstAndLast(totalPages);
-                default:
-                    throw new IllegalArgumentException("Unsupported custom mode");
-            }
-        } catch (IllegalArgumentException e) {
-            logger.error("Unsupported custom mode", e);
-            return null;
-        }
-    }
+			// Remove all the pages from the original document
+			for (int i = document.getNumberOfPages() - 1; i >= 0; i--) {
+				document.removePage(i);
+			}
 
-    @PostMapping(consumes = "multipart/form-data", value = "/rearrange-pages")
-    @Operation(summary = "Rearrange pages in a PDF file",
-            description = "This endpoint rearranges pages in a given PDF file based on the specified page order or custom mode. Users can provide a page order as a comma-separated list of page numbers or page ranges, or a custom mode.")
-    public ResponseEntity<byte[]> rearrangePages(
-            @RequestPart(required = true, value = "fileInput")
-            @Parameter(description = "The input PDF file to rearrange pages")
-                    MultipartFile pdfFile,
-            @RequestParam(required = false, value = "pageOrder")
-            @Parameter(description = "The new page order as a comma-separated list of page numbers or page ranges (e.g., '1,3,5-7')")
-                    String pageOrder,
-            @RequestParam(required = false, value = "customMode")
-            @Parameter(schema = @Schema(implementation = CustomMode.class, description = "The custom mode for page rearrangement. " +
-            	    "Valid values are:\n" +
-            	    "REVERSE_ORDER: Reverses the order of all pages.\n" +
-            	    "DUPLEX_SORT: Sorts pages as if all fronts were scanned then all backs in reverse (1, n, 2, n-1, ...). " +
-            	    "BOOKLET_SORT: Arranges pages for booklet printing (last, first, second, second last, ...).\n" +
-            	    "ODD_EVEN_SPLIT: Splits and arranges pages into odd and even numbered pages.\n" +
-            	    "REMOVE_FIRST: Removes the first page.\n" +
-            	    "REMOVE_LAST: Removes the last page.\n" +
-            	    "REMOVE_FIRST_AND_LAST: Removes both the first and the last pages.\n"))
-                    String customMode) {
-        try {
-            // Load the input PDF
-            PDDocument document = PDDocument.load(pdfFile.getInputStream());
+			// Add the pages in the new order
+			for (PDPage page : newPages) {
+				document.addPage(page);
+			}
 
-            // Split the page order string into an array of page numbers or range of numbers
-            String[] pageOrderArr = pageOrder != null ? pageOrder.split(",") : new String[0];
-            int totalPages = document.getNumberOfPages();
-            System.out.println("pageOrder=" + pageOrder);
-            System.out.println("customMode length =" + customMode.length());
-            List<Integer> newPageOrder;
-            if(customMode != null && customMode.length() > 0) {
-            	newPageOrder = processCustomMode(customMode, totalPages);
-            } else {
-            	newPageOrder = pageOrderToString(pageOrderArr, totalPages);
-            }
+			return WebResponseUtils.pdfDocToWebResponse(document,
+					pdfFile.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_rearranged.pdf");
+		} catch (IOException e) {
+			logger.error("Failed rearranging documents", e);
+			return null;
+		}
+	}
 
-            // Create a new list to hold the pages in the new order
-            List<PDPage> newPages = new ArrayList<>();
-            for (int i = 0; i < newPageOrder.size(); i++) {
-                newPages.add(document.getPage(newPageOrder.get(i)));
-            }
+	private List<Integer> pageOrderToString(String[] pageOrderArr, int totalPages) {
+	    List<Integer> newPageOrder = new ArrayList<>();
 
-            // Remove all the pages from the original document
-            for (int i = document.getNumberOfPages() - 1; i >= 0; i--) {
-                document.removePage(i);
-            }
+	    // loop through the page order array
+	    for (String element : pageOrderArr) {
+	        // check if the element contains a range of pages
+	        if (element.matches("\\d*n\\+?-?\\d*|\\d*\\+?n")) {
+	            // Handle page order as a function
+	            int coefficient = 0;
+	            int constant = 0;
+	            boolean coefficientExists = false;
+	            boolean constantExists = false;
 
-            // Add the pages in the new order
-            for (PDPage page : newPages) {
-                document.addPage(page);
-            }
+	            if (element.contains("n")) {
+	                String[] parts = element.split("n");
+	                if (!parts[0].equals("") && parts[0] != null) {
+	                    coefficient = Integer.parseInt(parts[0]);
+	                    coefficientExists = true;
+	                }
+	                if (parts.length > 1 && !parts[1].equals("") && parts[1] != null) {
+	                    constant = Integer.parseInt(parts[1]);
+	                    constantExists = true;
+	                }
+	            } else if (element.contains("+")) {
+	                constant = Integer.parseInt(element.replace("+", ""));
+	                constantExists = true;
+	            }
 
-            return WebResponseUtils.pdfDocToWebResponse(document, pdfFile.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_rearranged.pdf");
-        } catch (IOException e) {
-            logger.error("Failed rearranging documents", e);
-            return null;
-        }
-    }
+	            for (int i = 1; i <= totalPages; i++) {
+	                int pageNum = coefficientExists ? coefficient * i : i;
+	                pageNum += constantExists ? constant : 0;
 
+	                if (pageNum <= totalPages && pageNum > 0) {
+	                    newPageOrder.add(pageNum - 1);
+	                }
+	            }
+	        } else if (element.contains("-")) {
+	            // split the range into start and end page
+	            String[] range = element.split("-");
+	            int start = Integer.parseInt(range[0]);
+	            int end = Integer.parseInt(range[1]);
+	            // check if the end page is greater than total pages
+	            if (end > totalPages) {
+	                end = totalPages;
+	            }
+	            // loop through the range of pages
+	            for (int j = start; j <= end; j++) {
+	                // print the current index
+	                newPageOrder.add(j - 1);
+	            }
+	        } else {
+	            // if the element is a single page
+	            newPageOrder.add(Integer.parseInt(element) - 1);
+	        }
+	    }
+
+	    return newPageOrder;
+	}
 
 }
diff --git a/src/main/resources/messages_en_GB.properties b/src/main/resources/messages_en_GB.properties
index 5eee2506..04f7df53 100644
--- a/src/main/resources/messages_en_GB.properties
+++ b/src/main/resources/messages_en_GB.properties
@@ -10,7 +10,7 @@ multiPdfDropPrompt=Select (or drag & drop) all PDFs you require
 imgPrompt=Select Image(s)
 genericSubmit=Submit
 processTimeWarning=Warning: This process can take up to a minute depending on file-size
-pageOrderPrompt=Custom Page Order (Enter a comma-separated list of page numbers) :
+pageOrderPrompt=Custom Page Order (Enter a comma-separated list of page numbers or Functions like 2n+1) :
 goToPage=Go
 true=True
 false=False
diff --git a/src/main/resources/static/js/downloader.js b/src/main/resources/static/js/downloader.js
index 5dc1912f..35623db6 100644
--- a/src/main/resources/static/js/downloader.js
+++ b/src/main/resources/static/js/downloader.js
@@ -19,25 +19,9 @@ $(document).ready(function() {
 
 		try {
 			if (override === 'multi' || files.length > 1 && override !== 'single') {
-				// Show the progress bar
-				$('#progressBarContainer').show();
-				// Initialize the progress bar
-				//let progressBar = $('#progressBar');
-				//progressBar.css('width', '0%');
-				//progressBar.attr('aria-valuenow', 0);
-				//progressBar.attr('aria-valuemax', files.length);
-
 				await submitMultiPdfForm(url, files);
 			} else {
-				const downloadDetails = await handleSingleDownload(url, formData);
-				const downloadOption = localStorage.getItem('downloadOption');
-
-				// Handle the download action according to the selected option
-				//handleDownloadAction(downloadOption, downloadDetails.blob, downloadDetails.filename);
-
-				// Update the progress bar
-				//updateProgressBar(progressBar, 1);
-
+				await handleSingleDownload(url, formData);
 			}
 
 			$('#submitBtn').text('Submit');
@@ -49,29 +33,9 @@ $(document).ready(function() {
 	});
 });
 
-function handleDownloadAction(downloadOption, blob, filename) {
-	const url = URL.createObjectURL(blob);
 
-	switch (downloadOption) {
-		case 'sameWindow':
-			// Open the file in the same window
-			window.location.href = url;
-			break;
-		case 'newWindow':
-			// Open the file in a new window
-			window.open(url, '_blank');
-			break;
-		default:
-			// Download the file
-			const link = document.createElement('a');
-			link.href = url;
-			link.download = filename;
-			link.click();
-			break;
-	}
-}
 
-async function handleSingleDownload(url, formData) {
+async function handleSingleDownload(url, formData, isMulti = false) {
 	try {
 		const response = await fetch(url, { method: 'POST', body: formData });
 		const contentType = response.headers.get('content-type');
@@ -90,7 +54,7 @@ async function handleSingleDownload(url, formData) {
 		const blob = await response.blob();
 
 		if (contentType.includes('application/pdf') || contentType.includes('image/')) {
-			return handleResponse(blob, filename, true);
+			return handleResponse(blob, filename, !isMulti);
 		} else {
 			return handleResponse(blob, filename);
 		}
@@ -118,7 +82,7 @@ function getFilenameFromContentDisposition(contentDisposition) {
 async function handleJsonResponse(response) {
 	const json = await response.json();
 	const errorMessage = JSON.stringify(json, null, 2);
-	if (errorMessage.toLowerCase().includes('the password is incorrect') || errorMessage.toLowerCase().includes('Password is not provided')) {
+	if (errorMessage.toLowerCase().includes('the password is incorrect') || errorMessage.toLowerCase().includes('Password is not provided') || errorMessage.toLowerCase().includes('PDF contains an encryption dictionary')) {
 		alert('[[#{error.pdfPassword}]]');
 	} else {
 		showErrorBanner(json.error + ':' + json.message, json.trace);
@@ -173,10 +137,15 @@ async function submitMultiPdfForm(url, files) {
 	const zipThreshold = parseInt(localStorage.getItem('zipThreshold'), 10) || 4;
 	const zipFiles = files.length > zipThreshold;
 	let jszip = null;
-	//let progressBar = $('#progressBar');
-	//progressBar.css('width', '0%');
-	//progressBar.attr('aria-valuenow', 0);
-	//progressBar.attr('aria-valuemax', Array.from(files).length);
+	// Show the progress bar
+	$('#progressBarContainer').show();
+	// Initialize the progress bar
+	
+	let progressBar = $('#progressBar');
+	progressBar.css('width', '0%');
+	progressBar.attr('aria-valuenow', 0);
+	progressBar.attr('aria-valuemax', files.length);
+	
 	if (zipFiles) {
 		jszip = new JSZip();
 	}
@@ -202,20 +171,21 @@ async function submitMultiPdfForm(url, files) {
 			}
 
 			try {
-				const downloadDetails = await handleSingleDownload(url, fileFormData);
+				const downloadDetails = await handleSingleDownload(url, fileFormData, true);
 				console.log(downloadDetails);
 				if (zipFiles) {
 					jszip.file(downloadDetails.filename, downloadDetails.blob);
 				} else {
 					downloadFile(downloadDetails.blob, downloadDetails.filename);
 				}
-				//updateProgressBar(progressBar, Array.from(files).length);
+				updateProgressBar(progressBar, Array.from(files).length);
 			} catch (error) {
 				handleDownloadError(error);
 				console.error(error);
 			}
 		});
 		await Promise.all(promises);
+		
 	}
 
 	if (zipFiles) {
@@ -226,6 +196,8 @@ async function submitMultiPdfForm(url, files) {
 			console.error('Error generating ZIP file: ' + error);
 		}
 	}
+	progressBar.css('width',  '100%');
+	progressBar.attr('aria-valuenow', Array.from(files).length);
 }
 
 
diff --git a/src/main/resources/templates/pdf-organizer.html b/src/main/resources/templates/pdf-organizer.html
index 580f88a0..6accc45f 100644
--- a/src/main/resources/templates/pdf-organizer.html
+++ b/src/main/resources/templates/pdf-organizer.html
@@ -31,7 +31,7 @@
 						    </div>
                             <div class="form-group">
                                 <label for="pageOrder" th:text="#{pageOrderPrompt}"></label> 
-                                <input type="text" class="form-control" id="pageOrder" name="pageOrder" placeholder="(e.g. 1,3,2 or 4-8,2,10-12)" required>
+                                <input type="text" class="form-control" id="pageOrder" name="pageOrder" placeholder="(e.g. 1,3,2 or 4-8,2,10-12 or 2n-1)" required>
                             </div>
                             
                             <button type="submit" id="submitBtn" class="btn btn-primary" th:text="#{pdfOrganiser.submit}"></button>