try finally 妙用,防止内存泄漏_javascript技巧

[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]

这种写法在IE中100%内存泄漏

使用try finally很容易解决些问题

function createButton(){
var obj = document.createElement("button");
obj.innerHTML="点我!";
obj.onclick=function(){
//处理click事件
}
obj.onmouseover=function(){
//处理mouseover事件
}
try{
return obj;
}finally{
obj = null;//这句话在return 之后才执行,有效地解决了需在return后将obj置null的问题
}
}

一个函数或方法中，其实有很多地方都需要这种选返回值，最后执行某些事的

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附一:JavaScript Error (try/catch/finally)
Introduction
Like other programming languages, JavaScript provides the possibility to make use of
the try/catch/finally block. Usually when an error is encountered then the script stops and doesn't
continue with the rest of the page. The try/catch/finally block can be used to continue the
processing with the rest of the page. You just have to put the code in your try block and when
an error in encountered there, then it will call the catch block. The finally block is called always
regardless of an error occurred or not. The following example makes the usage clear.

Example:

<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]