Fix #686

Store the multiselectID to the widget instance and use that in refresh
methods to prevent creating collisions in input IDs.

src/jquery.multiselect.js

@@ -19,7 +19,7 @@
  *
  */
 (function($, undefined) {
-
+  // Counter used to prevent collisions
   var multiselectID = 0;
   var $doc = $(document);
 
@@ -77,6 +77,8 @@
       // factory cannot unbind automatically. Use eventNamespace if on
       // jQuery UI 1.9+, and otherwise fallback to a custom string.
       this._namespaceID = this.eventNamespace || ('multiselect' + multiselectID);
+      // bump unique ID after assigning it to the widget instance
+      this.multiselectID = multiselectID++;
 
       var button = (this.button = $('<button type="button"><span class="ui-icon ui-icon-triangle-1-s"></span></button>'))
         .addClass('ui-multiselect ui-widget ui-state-default ui-corner-all')
@@ -133,9 +135,6 @@
         if(!o.multiple) {
           this.menu.addClass('ui-multiselect-single');
         }
-
-        // bump unique ID
-        multiselectID++;
         el.hide();
     },
 
@@ -159,8 +158,8 @@
     _makeOption: function(option) {
       var title = option.title ? option.title : null;
       var value = option.value;
-      var id = this.element.attr('id') || multiselectID; // unique ID for the label & option tags
-      var inputID = 'ui-multiselect-' + multiselectID + '-' + (option.id || id + '-option-' + this.inputIdCounter++);
+      var id = this.element.attr('id') || this.multiselectID; // unique ID for the label & option tags
+      var inputID = 'ui-multiselect-' + this.multiselectID + '-' + (option.id || id + '-option-' + this.inputIdCounter++);
       var isDisabled = option.disabled;
       var isSelected = option.selected;
       var labelClasses = [ 'ui-corner-all' ];

tests/unit/events.js

@@ -127,6 +127,22 @@
 		el.multiselect("destroy").remove();
 	});
 
+	test("multiselectclick with multiple widgets", function() {
+		expect(3);
+		var first = $("<select multiple><option value='1'>Option 1</option><option value='2'>Option 2</option></select>").appendTo(body).multiselect();
+		var second = $("<select multiple><option value='1'>Option 1</option><option value='2'>Option 2</option></select>").appendTo(body).multiselect();
+		equals($('.ui-multiselect').length, 2, "two mutliselects are on the page");
+		first.multiselect("refresh");
+		second.multiselect("refresh");
+		$label = $(second.multiselect("getLabels")[0]);
+		$wrongInput = $(first.multiselect("getLabels")[0]).find("input");
+		$label.click();
+		equals($label.find("input").prop("checked"), true, "the input for that label should be checked");
+		equals($wrongInput.prop("checked"), false, "the input for the corresponding label on the first widget should not be checked");
+		first.multiselect("destroy").remove();
+		second.multiselect("destroy").remove();
+	});
+
 	test("multiselectclick", function(){
 		expect(28);