神游志

在javascript中调用 document.getElementById('elementId'); 如果那个元素不存在的话会返回 null 。而在jquery中调用 $('#elementId'); (其他的selector也一样)却无论那个元素存不存在都会返回一个jquery对象，所以不能在用 null 来判断了。根据 jquery的文档 判断存不存在方法为 if($('#elementId').length) 。

得到焦点：element.focus(); 选中其中内容：element.select(); 得到焦点时选中内容：<element onfocus="this.select();" />

Firefox only javascirpt: function OpacityElement(element) { this.targetElement = element; this.opacity = 1.0; this.display = null; } OpacityElement.prototype = { intervalFun: null , timeoutFun: null , handleEvent: function(t) { switch(t) { case 1: this.opacity -= 0.04; this.targetElement.style.opacity = this.opacity; break; case 2: this.opacity = 0.0; this.targetElement.style.opacity = 0.0; this.display = this.targetElement.style.display; this.targetElement.style.display = 'none'; clearInterval(this.intervlaFun); clearTimeout(this.timeoutFun); break; case 3: this.opacity += 0.04; this.targetElement.style.opacity = this.opacity; break; case 4: this.opacity = 1.0; this.targetElement.style.opacity = 1.0; clearInterval(this.intervlaFun); clearTimeout(this.timeoutFun); break; } } , Hidden: function() { var self = this; this.intervlaFun = setInterval( function() { self.handleEve...