body {font-size:14px;}
function chkmail(o){
var reeml = /^[\w\-\.]+@[a-z0-9]+(\-[a-z0-9]+)?(\.[a-z0-9]+(\-[a-z0-9]+)?)*\.[a-z]{2,4}$/i;
var isok=reeml.test(o.value);
if (isok==false){
alert("请输入正确的邮箱地址!");
o.focus();
}
return isok
}
[ctrl+a 全选 注:如需引入外部js需刷新才能执行]