zmmbreeze/fif.js

## fif.js
(function(url){
    // 第一部分
    var dom,doc,where,iframe = document.createElement('iframe');
    iframe.src = "javascript:false";
    iframe.title = ""; iframe.role="presentation";
    (iframe.frameElement || iframe).style.cssText = "width: 0; height: 0; border: 0";
    where = document.getElementsByTagName('script');
    where = where[where.length - 1];
    where.parentNode.insertBefore(iframe, where);

    // 第二部分
    try {
        doc = iframe.contentWindow.document;
    } catch(e) {
        // IE下如果主页面修改过document.domain，那么访问用js创建的匿名iframe会发生跨域问题，必须通过js伪协议修改iframe内部的domain
        dom = document.domain;
        iframe.src="javascript:var d=document.open();d.domain='"+dom+"';void(0);";
        doc = iframe.contentWindow.document;
    }
    doc.open()._l = function() {
        var js = this.createElement("script");
        if(dom) this.domain = dom;
        js.id = "js-iframe-async";
        js.src = url;
        this.body.appendChild(js);
    };
    doc.write('<body onload="document._l();">');
    doc.close();
})('test.js');
	(function(url){
	// 第一部分
	var dom,doc,where,iframe = document.createElement('iframe');
	iframe.src = "javascript:false";
	iframe.title = ""; iframe.role="presentation";
	(iframe.frameElement \|\| iframe).style.cssText = "width: 0; height: 0; border: 0";
	where = document.getElementsByTagName('script');
	where = where[where.length - 1];
	where.parentNode.insertBefore(iframe, where);

	// 第二部分
	try {
	doc = iframe.contentWindow.document;
	} catch(e) {
	// IE下如果主页面修改过document.domain，那么访问用js创建的匿名iframe会发生跨域问题，必须通过js伪协议修改iframe内部的domain
	dom = document.domain;
	iframe.src="javascript:var d=document.open();d.domain='"+dom+"';void(0);";
	doc = iframe.contentWindow.document;
	}
	doc.open()._l = function() {
	var js = this.createElement("script");
	if(dom) this.domain = dom;
	js.id = "js-iframe-async";
	js.src = url;
	this.body.appendChild(js);
	};
	doc.write('<body onload="document._l();">');
	doc.close();
	})('test.js');