Update the leaflet zoom slider plugin to fix IE8

vendor/assets/leaflet/leaflet.zoom.js

@@ -7,28 +7,42 @@ L.Control.Zoomslider = L.Control.extend({
 
 	onAdd: function (map) {
 		var className = 'leaflet-control-zoomslider',
-			container = L.DomUtil.create('div', className);
-		
-        this._map = map;
+				container = L.DomUtil.create('div', className);
 
-		this._createButton('Zoom in', className + '-in'
-						   , container, this._zoomIn , this);
+		L.DomEvent
+			.on(container, 'click', L.DomEvent.stopPropagation)
+			.on(container, 'mousedown', L.DomEvent.stopPropagation)
+			.on(container, 'dblclick', L.DomEvent.stopPropagation);
+		
+		this._map = map;
+
+		this._zoomInButton = this._createButton('+', 'Zoom in', className + '-in'
+												, container, this._zoomIn , this);
 		this._createSlider(className + '-slider', container, map);
-		this._createButton('Zoom out', className + '-out'
-						   , container, this._zoomOut, this);
-
+		this._zoomOutButton = this._createButton('-', 'Zoom out', className + '-out'
+												 , container, this._zoomOut, this);
 		
-		
-		this._map.on('zoomend', this._snapToSliderValue, this);
+		map.on('layeradd layerremove', this._refresh, this);
+
+		map.whenReady(function(){
+			this._snapToSliderValue();
+			map.on('zoomend', this._snapToSliderValue, this);
+		}, this);
 
-		this._snapToSliderValue();
 		return container;
 	},
 
 	onRemove: function(map){
 		map.off('zoomend', this._snapToSliderValue);
+		map.off('layeradd layerremove', this._refresh);
 	},
-	
+
+	_refresh: function(){
+		this._map
+			.removeControl(this)
+			.addControl(this);
+	},
+
 	_createSlider: function (className, container, map) {
 		var zoomLevels = map.getMaxZoom() - map.getMinZoom();
 		this._sliderHeight = this.options.stepHeight * zoomLevels;
@@ -40,11 +54,8 @@ L.Control.Zoomslider = L.Control.extend({
 
 		this._draggable = this._createDraggable();
 		this._draggable.enable();
-		
-		L.DomEvent
-			.on(slider, 'click', L.DomEvent.stopPropagation)
-			.on(slider, 'click', L.DomEvent.preventDefault)
-			.on(slider, 'click', this._onSliderClick, this);
+
+		L.DomEvent.on(slider, 'click', this._onSliderClick, this);
 
 		return slider;
 	},
@@ -57,16 +68,16 @@ L.Control.Zoomslider = L.Control.extend({
 	    this._map.zoomOut(e.shiftKey ? 3 : 1);
 	},
 
-	_createButton: function (title, className, container, fn, context) {
+	_createButton: function (html, title, className, container, fn, context) {
 		var link = L.DomUtil.create('a', className, container);
+		link.innerHTML = html;
 		link.href = '#';
 		link.title = title;
 
 		L.DomEvent
-			.on(link, 'click', L.DomEvent.stopPropagation)
-			.on(link, 'click', L.DomEvent.preventDefault)
-			.on(link, 'click', fn, context);
-		
+		    .on(link, 'click', L.DomEvent.preventDefault)
+		    .on(link, 'click', fn, context);
+
 		return link;
 	},
 
@@ -79,15 +90,15 @@ L.Control.Zoomslider = L.Control.extend({
 			.on(this._knob, 'click', L.DomEvent.stopPropagation);
 
 		var bounds = new L.Bounds(
-			new L.Point(0, 0), 
+			new L.Point(0, 0),
 			new L.Point(0, this._sliderHeight)
 		);
-		var draggable = new L.BoundedDraggable(this._knob, 
-											   this._knob, 
+		var draggable = new L.BoundedDraggable(this._knob,
+											   this._knob,
 											   bounds)
 			.on('drag', this._snap, this)
 			.on('dragend', this._setZoom, this);
-		
+
 		return draggable;
 	},
 
@@ -100,9 +111,9 @@ L.Control.Zoomslider = L.Control.extend({
 
 	_onSliderClick: function(e){
 		var first = (e.touches && e.touches.length === 1 ? e.touches[0] : e);
-	    var offset = first.offsetY 
+	    var offset = first.offsetY
 			? first.offsetY
-			: L.DomEvent.getMousePosition(first).y 
+			: L.DomEvent.getMousePosition(first).y
 			- L.DomUtil.getViewportOffset(this._knob).y;
 		var value = this._posToSliderValue(offset - this._knob.offsetHeight / 2);
 		this._snapToSliderValue(value);
@@ -110,18 +121,19 @@ L.Control.Zoomslider = L.Control.extend({
 	},
 
 	_posToSliderValue: function(pos) {
-		pos = isNaN(pos) 
+		pos = isNaN(pos)
 			? L.DomUtil.getPosition(this._knob).y
-			: pos
+			: pos;
 		return Math.round( (this._sliderHeight - pos) / this.options.stepHeight);
 	},
 
 	_snapToSliderValue: function(sliderValue) {
+		this._updateDisabled();
 		if(this._knob) {
-			sliderValue = isNaN(sliderValue) 
+			sliderValue = isNaN(sliderValue)
 				? this._getSliderValue()
 				: sliderValue;
-			var y = this._sliderHeight 
+			var y = this._sliderHeight
 				- (sliderValue * this.options.stepHeight);
 			L.DomUtil.setPosition(this._knob, new L.Point(0, y));
 		}
@@ -134,6 +146,21 @@ L.Control.Zoomslider = L.Control.extend({
 	},
 	_getSliderValue: function(){
 		return this._toSliderValue(this._map.getZoom());
+	},
+
+	_updateDisabled: function () {
+		var map = this._map,
+			className = 'leaflet-control-zoomslider-disabled';
+
+		L.DomUtil.removeClass(this._zoomInButton, className);
+		L.DomUtil.removeClass(this._zoomOutButton, className);
+
+		if (map.getZoom() === map.getMinZoom()) {
+			L.DomUtil.addClass(this._zoomOutButton, className);
+		}
+		if (map.getZoom() === map.getMaxZoom()) {
+			L.DomUtil.addClass(this._zoomInButton, className);
+		}
 	}
 });
 
@@ -144,8 +171,7 @@ L.Map.mergeOptions({
 
 L.Map.addInitHook(function () {
     if (this.options.zoomsliderControl) {
-		this.zoomsliderControl = new L.Control.Zoomslider();
-		this.addControl(this.zoomsliderControl);
+		L.control.zoomslider().addTo(this);
 	}
 });
 
@@ -163,7 +189,7 @@ L.BoundedDraggable = L.Draggable.extend({
 				this._newPos = this._fitPoint(this._newPos);
 			}
 		}, this);
-	}, 
+	},
 	_fitPoint: function(point){
 		var closest = new L.Point(
 			Math.min(point.x, this._bounds.max.x),