keypress on autocomplete is not firing why?

$("#subSiteTitle").keypress(function () {
    alert('hello!');
}

/*!
 * jQuery UI Autocomplete 1.11.2
 * http://jqueryui.com
 *
 * Copyright 2014 jQuery Foundation and other contributors
 * Released under the MIT license.
 * http://jquery.org/license
 *
 * http://api.jqueryui.com/autocomplete/
 */


$.widget( "ui.autocomplete", {
	version: "1.11.2",
	defaultElement: "<input>",
	options: {
		appendTo: null,
		autoFocus: false,
		delay: 300,
		minLength: 1,
		position: {
			my: "left top",
			at: "left bottom",
			collision: "none"
		},
		source: null,

		// callbacks
		change: null,
		close: null,
		focus: null,
		open: null,
		response: null,
		search: null,
		select: null
	},

	requestIndex: 0,
	pending: 0,

	_create: function() {
		// Some browsers only repeat keydown events, not keypress events,
		// so we use the suppressKeyPress flag to determine if we've already
		// handled the keydown event. #7269
		// Unfortunately the code for & in keypress is the same as the up arrow,
		// so we use the suppressKeyPressRepeat flag to avoid handling keypress
		// events when we know the keydown event was used to modify the
		// search term. #7799
		var suppressKeyPress, suppressKeyPressRepeat, suppressInput,
			nodeName = this.element[ 0 ].nodeName.toLowerCase(),
			isTextarea = nodeName === "textarea",
			isInput = nodeName === "input";

		this.isMultiLine =
			// Textareas are always multi-line
			isTextarea ? true :
			// Inputs are always single-line, even if inside a contentEditable element
			// IE also treats inputs as contentEditable
			isInput ? false :
			// All other element types are determined by whether or not they're contentEditable
			this.element.prop( "isContentEditable" );

		this.valueMethod = this.element[ isTextarea || isInput ? "val" : "text" ];
		this.isNewMenu = true;

		this.element
			.addClass( "ui-autocomplete-input" )
			.attr( "autocomplete", "off" );

		this._on( this.element, {
			keydown: function( event ) {
				if ( this.element.prop( "readOnly" ) ) {
					suppressKeyPress = true;
					suppressInput = true;
					suppressKeyPressRepeat = true;
					return;
				}

				suppressKeyPress = false;
				suppressInput = false;
				suppressKeyPressRepeat = false;
				var keyCode = $.ui.keyCode;
				switch ( event.keyCode ) {
				case keyCode.PAGE_UP:
					suppressKeyPress = true;
					this._move( "previousPage", event );
					break;
				case keyCode.PAGE_DOWN:
					suppressKeyPress = true;
					this._move( "nextPage", event );
					break;
				case keyCode.UP:
					suppressKeyPress = true;
					this._keyEvent( "previous", event );
					break;
				case keyCode.DOWN:
					suppressKeyPress = true;
					this._keyEvent( "next", event );
					break;
				case keyCode.ENTER:
					// when menu is open and has focus
					if ( this.menu.active ) {
						// #6055 - Opera still allows the keypress to occur
						// which causes forms to submit
						suppressKeyPress = true;
						event.preventDefault();
						this.menu.select( event );
					}
					break;
				case keyCode.TAB:
					if ( this.menu.active ) {
						this.menu.select( event );
					}
					break;
				case keyCode.ESCAPE:
					if ( this.menu.element.is( ":visible" ) ) {
						if ( !this.isMultiLine ) {
							this._value( this.term );
						}
						this.close( event );
						// Different browsers have different default behavior for escape
						// Single press can mean undo or clear
						// Double press in IE means clear the whole form
						event.preventDefault();
					}
					break;
				default:
					suppressKeyPressRepeat = true;
					// search timeout should be triggered before the input value is changed
					this._searchTimeout( event );
					break;
				}
			},
			keypress: function( event ) {
				if ( suppressKeyPress ) {
					suppressKeyPress = false;
					if ( !this.isMultiLine || this.menu.element.is( ":visible" ) ) {
						event.preventDefault();
					}
					return;
				}
				if ( suppressKeyPressRepeat ) {
					return;
				}

				// replicate some key handlers to allow them to repeat in Firefox and Opera
				var keyCode = $.ui.keyCode;
				switch ( event.keyCode ) {
				case keyCode.PAGE_UP:
					this._move( "previousPage", event );
					break;
				case keyCode.PAGE_DOWN:
					this._move( "nextPage", event );
					break;
				case keyCode.UP:
					this._keyEvent( "previous", event );
					break;
				case keyCode.DOWN:
					this._keyEvent( "next", event );
					break;
				}
			},
			input: function( event ) {
				if ( suppressInput ) {
					suppressInput = false;
					event.preventDefault();
					return;
				}
				this._searchTimeout( event );
			},
			focus: function() {
				this.selectedItem = null;
				this.previous = this._value();
			},
			blur: function( event ) {
				if ( this.cancelBlur ) {
					delete this.cancelBlur;
					return;
				}

				clearTimeout( this.searching );
				this.close( event );
				this._change( event );
			}
		});

		this._initSource();
		this.menu = $( "<ul>" )
			.addClass( "ui-autocomplete ui-front" )
			.appendTo( this._appendTo() )
			.menu({
				// disable ARIA support, the live region takes care of that
				role: null
			})
			.hide()
			.menu( "instance" );

		this._on( this.menu.element, {
			mousedown: function( event ) {
				// prevent moving focus out of the text field
				event.preventDefault();

				// IE doesn't prevent moving focus even with event.preventDefault()
				// so we set a flag to know when we should ignore the blur event
				this.cancelBlur = true;
				this._delay(function() {
					delete this.cancelBlur;
				});

				// clicking on the scrollbar causes focus to shift to the body
				// but we can't 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 = this.menu.element[ 0 ];
				if ( !$( event.target ).closest( ".ui-menu-item" ).length ) {
					this._delay(function() {
						var that = this;
						this.document.one( "mousedown", function( event ) {
							if ( event.target !== that.element[ 0 ] &&
									event.target !== menuElement &&
									!$.contains( menuElement, event.target ) ) {
								that.close();
							}
						});
					});
				}
			},
			menufocus: function( event, ui ) {
				var label, item;
				// support: Firefox
				// Prevent accidental activation of menu items in Firefox (#7024 #9118)
				if ( this.isNewMenu ) {
					this.isNewMenu = false;
					if ( event.originalEvent && /^mouse/.test( event.originalEvent.type ) ) {
						this.menu.blur();

						this.document.one( "mousemove", function() {
							$( event.target ).trigger( event.originalEvent );
						});

						return;
					}
				}

				item = ui.item.data( "ui-autocomplete-item" );
				if ( false !== this._trigger( "focus", event, { item: item } ) ) {
					// use value to match what will end up in the input, if it was a key event
					if ( event.originalEvent && /^key/.test( event.originalEvent.type ) ) {
						this._value( item.value );
					}
				}

				// Announce the value in the liveRegion
				label = ui.item.attr( "aria-label" ) || item.value;
				if ( label && $.trim( label ).length ) {
					this.liveRegion.children().hide();
					$( "<div>" ).text( label ).appendTo( this.liveRegion );
				}
			},
			menuselect: function( event, ui ) {
				var item = ui.item.data( "ui-autocomplete-item" ),
					previous = this.previous;

				// only trigger when focus was lost (click on menu)
				if ( this.element[ 0 ] !== this.document[ 0 ].activeElement ) {
					this.element.focus();
					this.previous = previous;
					// #6109 - IE triggers two focus events and the second
					// is asynchronous, so we need to reset the previous
					// term synchronously and asynchronously :-(
					this._delay(function() {
						this.previous = previous;
						this.selectedItem = item;
					});
				}

				if ( false !== this._trigger( "select", event, { item: item } ) ) {
					this._value( item.value );
				}
				// reset the term after the select event
				// this allows custom select handling to work properly
				this.term = this._value();

				this.close( event );
				this.selectedItem = item;
			}
		});

		this.liveRegion = $( "<span>", {
				role: "status",
				"aria-live": "assertive",
				"aria-relevant": "additions"
			})
			.addClass( "ui-helper-hidden-accessible" )
			.appendTo( this.document[ 0 ].body );

		// turning off autocomplete prevents the browser from remembering the
		// value when navigating through history, so we re-enable autocomplete
		// if the page is unloaded before the widget is destroyed. #7790
		this._on( this.window, {
			beforeunload: function() {
				this.element.removeAttr( "autocomplete" );
			}
		});
	},

	_destroy: function() {
		clearTimeout( this.searching );
		this.element
			.removeClass( "ui-autocomplete-input" )
			.removeAttr( "autocomplete" );
		this.menu.element.remove();
		this.liveRegion.remove();
	},

	_setOption: function( key, value ) {
		this._super( key, value );
		if ( key === "source" ) {
			this._initSource();
		}
		if ( key === "appendTo" ) {
			this.menu.element.appendTo( this._appendTo() );
		}
		if ( key === "disabled" && value && this.xhr ) {
			this.xhr.abort();
		}
	},

	_appendTo: function() {
		var element = this.options.appendTo;

		if ( element ) {
			element = element.jquery || element.nodeType ?
				$( element ) :
				this.document.find( element ).eq( 0 );
		}

		if ( !element || !element[ 0 ] ) {
			element = this.element.closest( ".ui-front" );
		}

		if ( !element.length ) {
			element = this.document[ 0 ].body;
		}

		return element;
	},

	_initSource: function() {
		var array, url,
			that = this;
		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 ( that.xhr ) {
					that.xhr.abort();
				}
				that.xhr = $.ajax({
					url: url,
					data: request,
					dataType: "json",
					success: function( data ) {
						response( data );
					},
					error: function() {
						response([]);
					}
				});
			};
		} else {
			this.source = this.options.source;
		}
	},

	_searchTimeout: function( event ) {
		clearTimeout( this.searching );
		this.searching = this._delay(function() {

			// Search if the value has changed, or if the user retypes the same value (see #7434)
			var equalValues = this.term === this._value(),
				menuVisible = this.menu.element.is( ":visible" ),
				modifierKey = event.altKey || event.ctrlKey || event.metaKey || event.shiftKey;

			if ( !equalValues || ( equalValues && !menuVisible && !modifierKey ) ) {
				this.selectedItem = null;
				this.search( null, event );
			}
		}, this.options.delay );
	},

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

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

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

		if ( this._trigger( "search", event ) === false ) {
			return;
		}

		return this._search( value );
	},

	_search: function( value ) {
		this.pending++;
		this.element.addClass( "ui-autocomplete-loading" );
		this.cancelSearch = false;

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

	_response: function() {
		var index = ++this.requestIndex;

		return $.proxy(function( content ) {
			if ( index === this.requestIndex ) {
				this.__response( content );
			}

			this.pending--;
			if ( !this.pending ) {
				this.element.removeClass( "ui-autocomplete-loading" );
			}
		}, this );
	},

	__response: function( content ) {
		if ( content ) {
			content = this._normalize( content );
		}
		this._trigger( "response", null, { content: content } );
		if ( !this.options.disabled && content && content.length && !this.cancelSearch ) {
			this._suggest( content );
			this._trigger( "open" );
		} else {
			// use ._close() instead of .close() so we don't cancel future searches
			this._close();
		}
	},

	close: function( event ) {
		this.cancelSearch = true;
		this._close( event );
	},

	_close: function( event ) {
		if ( this.menu.element.is( ":visible" ) ) {
			this.menu.element.hide();
			this.menu.blur();
			this.isNewMenu = true;
			this._trigger( "close", event );
		}
	},

	_change: function( event ) {
		if ( this.previous !== this._value() ) {
			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( {}, item, {
				label: item.label || item.value,
				value: item.value || item.label
			});
		});
	},

	_suggest: function( items ) {
		var ul = this.menu.element.empty();
		this._renderMenu( ul, items );
		this.isNewMenu = true;
		this.menu.refresh();

		// size and position menu
		ul.show();
		this._resizeMenu();
		ul.position( $.extend({
			of: this.element
		}, this.options.position ) );

		if ( this.options.autoFocus ) {
			this.menu.next();
		}
	},

	_resizeMenu: function() {
		var ul = this.menu.element;
		ul.outerWidth( Math.max(
			// Firefox wraps long text (possibly a rounding bug)
			// so we add 1px to avoid the wrapping (#7513)
			ul.width( "" ).outerWidth() + 1,
			this.element.outerWidth()
		) );
	},

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

	_renderItemData: function( ul, item ) {
		return this._renderItem( ul, item ).data( "ui-autocomplete-item", item );
	},

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

	_move: function( direction, event ) {
		if ( !this.menu.element.is( ":visible" ) ) {
			this.search( null, event );
			return;
		}
		if ( this.menu.isFirstItem() && /^previous/.test( direction ) ||
				this.menu.isLastItem() && /^next/.test( direction ) ) {

			if ( !this.isMultiLine ) {
				this._value( this.term );
			}

			this.menu.blur();
			return;
		}
		this.menu[ direction ]( event );
	},

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

	_value: function() {
		return this.valueMethod.apply( this.element, arguments );
	},

	_keyEvent: function( keyEvent, event ) {
		if ( !this.isMultiLine || this.menu.element.is( ":visible" ) ) {
			this._move( keyEvent, event );

			// prevents moving cursor to beginning/end of the text field in some browsers
			event.preventDefault();
		}
	}
});

$.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 );
		});
	}
});

// live region extension, adding a `messages` option
// NOTE: This is an experimental API. We are still investigating
// a full solution for string manipulation and internationalization.
$.widget( "ui.autocomplete", $.ui.autocomplete, {
	options: {
		messages: {
			noResults: "No search results.",
			results: function( amount ) {
				return amount + ( amount > 1 ? " results are" : " result is" ) +
					" available, use up and down arrow keys to navigate.";
			}
		}
	},

	__response: function( content ) {
		var message;
		this._superApply( arguments );
		if ( this.options.disabled || this.cancelSearch ) {
			return;
		}
		if ( content && content.length ) {
			message = this.options.messages.results( content.length );
		} else {
			message = this.options.messages.noResults;
		}
		this.liveRegion.children().hide();
		$( "<div>" ).text( message ).appendTo( this.liveRegion );
	}
});

var autocomplete = $.ui.autocomplete;