调用方式如下

<iframe id="ifm" name="ifm" οnlοad="SetIFrameHeight('ifm')" src="http://www.qq.com" />

function SetIFrameHeight(down) {var Sys = {};var ua = navigator.userAgent.toLowerCase();var s;(s = ua.match(/msie ([\d.]+)/)) ? Sys.ie = s[1] :(s = ua.match(/firefox\/([\d.]+)/)) ? Sys.firefox = s[1] :(s = ua.match(/chrome\/([\d.]+)/)) ? Sys.chrome = s[1] :(s = ua.match(/opera.([\d.]+)/)) ? Sys.opera = s[1] :(s = ua.match(/version\/([\d.]+).*safari/)) ? Sys.safari = s[1] : 0;var pTar = null;if (document.getElementById) {pTar = document.getElementById(down);} else {eval('pTar=' + down + ';');}pTar.style.display = "block";if (Sys.ie) {if (Sys.ie == '9.0') {pTar.height = pTar.contentWindow.document.body.offsetHeight + 15 + "px";pTar.width = pTar.contentWindow.document.body.scrollWidth + "px";} else if (Sys.ie == '8.0') {debugger;pTar.height = pTar.Document.body.offsetHeight + 15 + "px";pTar.width = pTar.Document.body.scrollWidth + "px";} else {pTar.height = pTar.Document.body.scrollHeight + 25 + "px";pTar.width = pTar.Document.body.scrollWidth + "px";}}if (Sys.firefox) {pTar.height = pTar.contentDocument.body.offsetHeight + 15 + "px";pTar.width = pTar.contentDocument.body.scrollWidth + "px";}if (Sys.chrome) {pTar.height = pTar.contentDocument.body.offsetHeight;pTar.width = pTar.contentDocument.body.scrollWidth;}if (Sys.opera) {pTar.height = pTar.contentDocument.body.offsetHeight;pTar.width = pTar.contentDocument.body.scrollWidth;}if (Sys.safari) {if (pTar.contentDocument.body.offsetHeight <= '186') {pTar.height = pTar.contentDocument.body.offsetHeight + 10;} else {pTar.height = pTar.contentDocument.body.offsetHeight;}pTar.width = pTar.contentDocument.body.scrollWidth;}}