为什么获取不到js全局变量--高分跪求大神帮我解决

qianfoyuan 2011-09-30 10:13:02

我要获取的确是 A.js 中全局变量 b,各位可以将下面代码拷下去,分成两个文件, A.js test.html.然后点击 test.html里面会生成一个 iframe 框架,但我要获取父窗体中 b 变量,但 IE Firefox 提示 b 未定义.跪求大神帮我解决,解决问题者给高分.万分感谢.

JS A页面:
function A()
{
this.x = 6;
this.y = 7;
}
var b = 5;

HTML 页面:
<html>
<head>
<script type="text/javascript" src="./A.js"></script>
<script type="text/javascript">
var x = 5;
var a = new A();
</script>
</head>
<body>
<input id = "readme" type = "text" value="helloworld"></input><br>
<script>
window.onload=function(){
var str="<div><iframe width=400 height=300 frameborder='yes' scrolling='no' style='position:absolute'></iframe></div>";
document.write(str);

var mystr = "";
mystr += "<html>";
mystr += " <head>";
mystr += " <script type='text/javascr" + "ipt' defer>";
mystr += " function func(){";
mystr += " var x=parent.b;document.getElementsByTagName('input')[0].value=x;"; mystr += " }";
mystr += " </" + "scr" + "ipt>";
mystr += " </head>";
mystr += " <body>";
mystr += " <input type='button' value='' onclick='func();'></input>";
mystr += " </body>";
mystr += "</head>";

window.frames[0].document.write(mystr);
window.frames[0].document.close();}
</script>
<p>一些老的浏览器不支持 iframe。</p>
<p>如果得不到支持，iframe 是不可见的。</p>
</body>
</html>

为什么不能获取不到 b 全局变量?

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峭沙 2011-09-30

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呵呵，document.write要慎用

qianfoyuan 2011-09-30

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非常感谢 axiheyhey 谢谢你了.

qianfoyuan 2011-09-30

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好谢谢三楼,非常谢三楼,我明白了,把
var str="<div><iframe width=400 height=300 frameborder='yes' scrolling='no' style='position:absolute'></iframe></div>";
document.write(str);放在window.onload外可以避免函数调用导致window销毁.同时也感谢二楼

峭沙 2011-09-30

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因为document.write(str);这句话，你把父窗口的所有元素，包括js全部清除掉了。。

<html>

<head>

<script type="text/javascript">

	function A(){

		this.x = 6;

		this.y = 7;

		alert(this.x);

	}

	c = 1;

	var b = 5;

	var x = 5;

	//var a = new A();

</script>

</head>

<body>

<input id = "readme" type = "text" value="helloworld"></input><br>

<script>

	window.onload=function(){

		//var str="<iframe width=400 height=300 frameborder='yes' scrolling='no' style='position:absolute'></iframe>";

		//document.write(str);

		var iframe = document.createElement('iframe');

		iframe.width = 400;

		iframe.height = 300;

		iframe.frameborder = 'yes';

		iframe.scrolling='no';

		iframe.style.position = 'absolute';

		document.body.appendChild(iframe);

		

		

		var mystr = "";

		mystr += "<html>";

		mystr += "	<head>";

		mystr += "	 <script type='text/javascr" + "ipt'>";

		mystr += "	 function func(){";

		mystr += "	 var x=parent.b;document.getElementsByTagName('input')[0].value=x;";

		mystr += "	 }";

		mystr += "	 </" + "scr" + "ipt>";

		mystr += "	</head>";

		mystr += "	<body>";

		mystr += "	 <input type='button' value='' onclick='func();'></input>";

		mystr += "	</body>";

		mystr += "</head></html>";

		window.frames[0].document.open();

		window.frames[0].document.write(mystr);

		window.frames[0].document.close();

	}

</script>

<p>一些老的浏览器不支持 iframe。</p>

<p>如果得不到支持，iframe 是不可见的。</p>

</body>

</html>