Question

上次我在谷歌研究内存泄漏，循环引用以及垃圾收集的工作原理。但一切都有点混乱。我明白垃圾收集工作方式是这样的：

var a = {}; // a is only reference to this object
a = 5 /* now variable a is reference to "number" (other js object)
and now the first empty object has no reference,
so it is cleaned from the memory. */

看起来很酷。但我看到在IE中有一个JScript对象和COM对象。如果COM和JScript中的对象之间存在循环引用，则存在内存泄漏（未清除的内存）。所以现在我已经融入并做了一些简单的例子来展示我理解或不理解：

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
    <div style="width: 30px;" id='myDiv'></div>
    <script language='javascript'>
    "use strict";
     var a = 4,
     i,
     div = document.createElement('div');

     //no leaks
     function noLeaks(b) {
         this.a = a;
         a = this.b;
     }
     var obj = new noLeaks(5);

     //leak pattern
    function makeLeaks(func) {
        div.badAttachToCOMObject = func; // the problem is here
    }
    makeLeaks(function(){}); //attach reference to JScript objcet/function?


    //no leaks
    function size() {
        return '30px'; //just a value
    }
    function noStyleLeaks() {
        div.style.width = size();
        /* DOM (COM in IE) element just get a value,
        not a reference, only if I put a object or
        function to the value is a problem? */
    }
    noStyleLeaks();

    //leaks or not
    function styleLeaks() {
        div.style.width = document.getElementById('myDiv').style.width;/* this
        is cycle reference, but maybe only between COM and COM objects?
        And do not make leaks? */
    }
    styleLeaks();
    </script>
</body>
</html>

我是否了解主要想法？还有最后一个问题，Chrome有一个任务管理器，当我使用http://www.javascriptkit.com/javatutors/closuresleak/index.shtml时，每次刷新时，Windows任务管理器显示内存使用量跳跃大约1mb：

function LeakMemory(){
    for(i = 0; i < 50000; i++){
        var parentDiv = 
        document.createElement("div");
    }
}

Chrome（21）泄漏？我认为这不正常。所以我对JS垃圾收集的工作方式越来越困惑。

内存泄漏，垃圾收集和引用

0 个答案: