function checkEmail (emailStr,errorMsg, needFlag) {

			var eStr=emailStr.value;

			var emailvalue=eStr.toLowerCase();
			
			var checkTLD=1;
			
			var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
			
			var emailPat=/^(.+)@(.+)$/;
			
			var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
			
			var validChars="\[^\\s" + specialChars + "\]";
			
			var quotedUser="(\"[^\"]*\")";
			
			var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
			
			var atom=validChars + '+';
			
			var word="(" + atom + "|" + quotedUser + ")";
			
			
			var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
			
			
			var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
			
			var matchArray=emailvalue.match(emailPat);
			
			if (matchArray==null) {
			
			alert("电子邮件地址错误（请检查@和.是否输入正确）!");
			return false;
			}
			var user=matchArray[1];
			var domain=matchArray[2];
			
			for (i=0; i<user.length; i++) {
			if (user.charCodeAt(i)>127) {
			alert("该用户名含有非法/无效字符.");
			return false;
			   }
			}
			for (i=0; i<domain.length; i++) {
			if (domain.charCodeAt(i)>127) {
			alert("该域名含有非法/无效字符.");
			return false;
			   }
			}
			
			// See if "user" is valid 
			
			if (user.match(userPat)==null) {
			
			// user is not valid
			
			alert("该用户名错误或不存在.");
			return false;
			}
			
			/* if the e-mail address is at an IP address (as opposed to a symbolic
			host name) make sure the IP address is valid. */
			
			var IPArray=domain.match(ipDomainPat);
			if (IPArray!=null) {
			
			// this is an IP address
			
			for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) {
			alert("目标IP地址无效!");
			return false;
			   }
			}
			return true;
			}
			
			// Domain is symbolic name.  Check if it's valid.
			 
			var atomPat=new RegExp("^" + atom + "$");
			var domArr=domain.split(".");
			var len=domArr.length;
			for (i=0;i<len;i++) {
			if (domArr[i].search(atomPat)==-1) {
			alert("该域名无效.");
			return false;
			   }
			}
			
			/* domain name seems valid, but now make sure that it ends in a
			known top-level domain (like com, edu, gov) or a two-letter word,
			representing country (uk, nl), and that there's a hostname preceding 
			the domain or country. */
			
			if (checkTLD && domArr[domArr.length-1].length!=2 && 
			domArr[domArr.length-1].search(knownDomsPat)==-1) {
			alert("邮件地址必须以常用的域名或者2个字符的国家名结尾.");
			return false;
			}
			
			// Make sure there's a host name preceding the domain.
			
			if (len<2) {
			alert("该地址缺失一个主机名/系统网络名!");
			return false;
			}
			
			// If we've gotten this far, everything's valid!
			return true;
}

function checkEmailIndex (emailStr,errorMsg, needFlag) {
	checkEmail(emailStr,errorMsg, needFlag);
}