autocomplete.js

$.widget( "ui.autocomplete", {
	options: {
		appendTo: "body",
		delay: 300,
		minLength: 1,
		position: {
			my: "left top",
			at: "left bottom",
			collision: "none"
		},
		source: null
	},
	_create: function() {
		var self = this,
			doc = this.element[ 0 ].ownerDocument;
		this.element
			.addClass( "ui-autocomplete-input" )
			.attr( "autocomplete", "off" )
			// TODO verify these actually work as intended
			.attr({
				role: "textbox",
				"aria-autocomplete": "list",
				"aria-haspopup": "true"
			})
			.bind( "keydown.autocomplete", function( event ) {
				if ( self.options.disabled ) {
					return;
				}

				var keyCode = $.ui.keyCode;
				switch( event.keyCode ) {
				case keyCode.PAGE_UP:
					self._move( "previousPage", event );
					break;
				case keyCode.PAGE_DOWN:
					self._move( "nextPage", event );
					break;
				case keyCode.UP:
					self._move( "previous", event );
					// prevent moving cursor to beginning of text field in some browsers
					event.preventDefault();
					break;
				case keyCode.DOWN:
					self._move( "next", event );
					// prevent moving cursor to end of text field in some browsers
					event.preventDefault();
					break;
				case keyCode.ENTER:
				case keyCode.NUMPAD_ENTER:
					// when menu is open or has focus
					if ( self.menu.element.is( ":visible" ) ) {
						event.preventDefault();
					}
					//passthrough - ENTER and TAB both select the current element
				case keyCode.TAB:
					if ( !self.menu.active ) {
						return;
					}
					self.menu.select( event );
					break;
				case keyCode.ESCAPE:
					self.element.val( self.term );
					self.close( event );
					break;
				default:
					// keypress is triggered before the input value is changed
					clearTimeout( self.searching );
					self.searching = setTimeout(function() {
						// only search if the value has changed
						if ( self.term != self.element.val() ) {
							self.selectedItem = null;
							self.search( null, event );
						}
					}, self.options.delay );
					break;
				}
			})
			.bind( "focus.autocomplete", function() {
				if ( self.options.disabled ) {
					return;
				}

				self.selectedItem = null;
				self.previous = self.element.val();
			})
			.bind( "blur.autocomplete", function( event ) {
				if ( self.options.disabled ) {
					return;
				}

				clearTimeout( self.searching );
				// clicks on the menu (or a button to trigger a search) will cause a blur event
				self.closing = setTimeout(function() {
					self.close( event );
					self._change( event );
				}, 150 );
			});
		this._initSource();
		this.response = function() {
			return self._response.apply( self, arguments );
		};
		this.menu = $( "<ul></ul>" )
			.addClass( "ui-autocomplete" )
			.appendTo( $( this.options.appendTo || "body", doc )[0] )
			// prevent the close-on-blur in case of a "slow" click on the menu (long mousedown)
			.mousedown(function( event ) {
				// clicking on the scrollbar causes focus to shift to the body
				// but we cant detect a mouseup or a click immediately afterward
				// so we have to track the next mousedown and close the menu if
				// the user clicks somewhere outside of the autocomplete
				var menuElement = self.menu.element[ 0 ];
				if ( event.target === menuElement ) {
					setTimeout(function() {
						$( document ).one( 'mousedown', function( event ) {
							if ( event.target !== self.element[ 0 ] &&
								event.target !== menuElement &&
								!$.ui.contains( menuElement, event.target ) ) {
								self.close();
							}
						});
					}, 1 );
				}

				// use another timeout to make sure the blur-event-handler on the input was already triggered
				setTimeout(function() {
					clearTimeout( self.closing );
				}, 13);
			})
			.menu({
				focus: function( event, ui ) {
					var item = ui.item.data( "item.autocomplete" );
					if ( false !== self._trigger( "focus", null, { item: item } ) ) {
						// use value to match what will end up in the input, if it was a key event
						if ( /^key/.test(event.originalEvent.type) ) {
							self.element.val( item.value );
						}
					}
				},
				selected: function( event, ui ) {
					var item = ui.item.data( "item.autocomplete" ),
						previous = self.previous;

					// only trigger when focus was lost (click on menu)
					if ( self.element[0] !== doc.activeElement ) {
						self.element.focus();
						self.previous = previous;
					}

					if ( false !== self._trigger( "select", event, { item: item } ) ) {
						self.term = item.value;
						self.element.val( item.value );
					}

					self.close( event );
					self.selectedItem = item;
				},
				blur: function( event, ui ) {
					// don't set the value of the text field if it's already correct
					// this prevents moving the cursor unnecessarily
					if ( self.menu.element.is(":visible") &&
						( self.element.val() !== self.term ) ) {
						self.element.val( self.term );
					}
				}
			})
			.zIndex( this.element.zIndex() + 1 )
			// workaround for jQuery bug #5781 http://dev.jquery.com/ticket/5781
			.css({ top: 0, left: 0 })
			.hide()
			.data( "menu" );
		if ( $.fn.bgiframe ) {
			 this.menu.element.bgiframe();
		}
	},

	destroy: function() {
		this.element
			.removeClass( "ui-autocomplete-input" )
			.removeAttr( "autocomplete" )
			.removeAttr( "role" )
			.removeAttr( "aria-autocomplete" )
			.removeAttr( "aria-haspopup" );
		this.menu.element.remove();
		$.Widget.prototype.destroy.call( this );
	},

	_setOption: function( key, value ) {
		$.Widget.prototype._setOption.apply( this, arguments );
		if ( key === "source" ) {
			this._initSource();
		}
		if ( key === "appendTo" ) {
			this.menu.element.appendTo( $( value || "body", this.element[0].ownerDocument )[0] )
		}
	},

	_initSource: function() {
		var self = this,
			array,
			url;
		if ( $.isArray(this.options.source) ) {
			array = this.options.source;
			this.source = function( request, response ) {
				response( $.ui.autocomplete.filter(array, request.term) );
			};
		} else if ( typeof this.options.source === "string" ) {
			url = this.options.source;
			this.source = function( request, response ) {
				if (self.xhr) {
					self.xhr.abort();
				}
				self.xhr = $.getJSON( url, request, function( data, status, xhr ) {
					if ( xhr === self.xhr ) {
						response( data );
					}
					self.xhr = null;
				});
			};
		} else {
			this.source = this.options.source;
		}
	},

	search: function( value, event ) {
		value = value != null ? value : this.element.val();

		// always save the actual value, not the one passed as an argument
		this.term = this.element.val();

		if ( value.length < this.options.minLength ) {
			return this.close( event );
		}

		clearTimeout( this.closing );
		if ( this._trigger("search") === false ) {
			return;
		}

		return this._search( value );
	},

	_search: function( value ) {
		this.element.addClass( "ui-autocomplete-loading" );

		this.source( { term: value }, this.response );
	},

	_response: function( content ) {
		if ( content.length ) {
			content = this._normalize( content );
			this._suggest( content );
			this._trigger( "open" );
		} else {
			this.close();
		}
		this.element.removeClass( "ui-autocomplete-loading" );
	},

	close: function( event ) {
		clearTimeout( this.closing );
		if ( this.menu.element.is(":visible") ) {
			this._trigger( "close", event );
			this.menu.element.hide();
			this.menu.deactivate();
		}
	},
	
	_change: function( event ) {
		if ( this.previous !== this.element.val() ) {
			this._trigger( "change", event, { item: this.selectedItem } );
		}
	},

	_normalize: function( items ) {
		// assume all items have the right format when the first item is complete
		if ( items.length && items[0].label && items[0].value ) {
			return items;
		}
		return $.map( items, function(item) {
			if ( typeof item === "string" ) {
				return {
					label: item,
					value: item
				};
			}
			return $.extend({
				label: item.label || item.value,
				value: item.value || item.label
			}, item );
		});
	},

	_suggest: function( items ) {
		var ul = this.menu.element
				.empty()
				.zIndex( this.element.zIndex() + 1 ),
			menuWidth,
			textWidth;
		this._renderMenu( ul, items );
		// TODO refresh should check if the active item is still in the dom, removing the need for a manual deactivate
		this.menu.deactivate();
		this.menu.refresh();
		this.menu.element.show().position( $.extend({
			of: this.element
		}, this.options.position ));

		menuWidth = ul.width( "" ).outerWidth();
		textWidth = this.element.outerWidth();
		ul.outerWidth( Math.max( menuWidth, textWidth ) );
	},

	_renderMenu: function( ul, items ) {
		var self = this;
		$.each( items, function( index, item ) {
			self._renderItem( ul, item );
		});
	},

	_renderItem: function( ul, item) {
		return $( "<li></li>" )
			.data( "item.autocomplete", item )
			.append( $( "<a></a>" ).text( item.label ) )
			.appendTo( ul );
	},

	_move: function( direction, event ) {
		if ( !this.menu.element.is(":visible") ) {
			this.search( null, event );
			return;
		}
		if ( this.menu.first() && /^previous/.test(direction) ||
				this.menu.last() && /^next/.test(direction) ) {
			this.element.val( this.term );
			this.menu.deactivate();
			return;
		}
		this.menu[ direction ]( event );
	},

	widget: function() {
		return this.menu.element;
	}
});

$.extend( $.ui.autocomplete, {
	escapeRegex: function( value ) {
		return value.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
	},
	filter: function(array, term) {
		var matcher = new RegExp( $.ui.autocomplete.escapeRegex(term), "i" );
		return $.grep( array, function(value) {
			return matcher.test( value.label || value.value || value );
		});
	}
});