IE7以下不兼容JS的onsubmit方法

在测试浏览器兼容问题时，发现IE6、IE7不支持在Javascript中调用form对象的onsubmit方法，本方法用于兼容IE6、IE7下对onsubmit方法的支持，各大浏览器均测试过。

function checkIE() { // 检查IE版本号，非IE浏览器返回null

var appName = navigator.appName,

userAgent = navigator.userAgent,version,versionfloat;

if (appName == 'Microsoft Internet Explorer') {

version = /MSIE\s(\S)/.exec(userAgent)[1];

versionfloat = parseFloat(version);

return versionfloat;

}

return null;

}

function onsubmitForm(formId){// 可传入表单对象或者表单ID

var form1;

if('object'==typeof(formId) && formId.tagName=="FORM"){

form1 = formId;

}else{

form1 = document.getElementById(formId);

}

var num = checkIE(),bool=false;

if(num>7||num==null)bool = true;

if(bool){

form1.onsubmit();

}else{

var uniqId = form1.uniqueID;

var str = form1.onsubmit+'';

var reg = /^function/;

var isFunction = reg.test(str);

if(isFunction){

str = str.replace('function onsubmit()', 'function onsubmit_'+uniqId+'()');

}else{

str = 'function onsubmit_'+uniqId+'(){' + str + '}';

}

eval(str);

eval('onsubmit_'+uniqId+'()');

}

}