jQuery - handle the CSS classes in inline label form

jquery-handle-css-inline-form.js

//http://www.narga.net/making-awesome-forms-inline-labels-with-jquery
    $("#signup input").focus(function() {
        if($(this).prev("label").html()+"..." == this.value){
            $(this).addClass("focus").setCursorPosition(0);
        }
    });
    $("#signup input").keypress(function() {
        if($(this).prev("label").html()+"..." == this.value){
            this.value = "";
            $(this).removeClass("focus").addClass("typing"
        }
    });
    $("#signup input").blur(function() {
		$(this).removeClass("focus").removeClass("typing"
		if(this.value == ""){
		this.value = $(this).prev("label").html()+"...";
		}
    });