用JS验证邮箱的合法性

 <script type="text/javascript">
var sText = document.getElementById('mail').value;

//onblur 为控件失去焦点事件

document.getElementById('mail').onblur = function sValue(){
sText = this.value;
var reMail =/^(?:[a-zA-Z0-9]+[_\-\+\.]?)*[a-zA-Z0-9]+@(?:([a-zA-Z0-9]+[_\-]?)*[a-zA-Z0-9]+\.)+([a-zA-Z]{2,})+$/;
var s=new RegExp(reMail);

if(s.test(sText))
{alert("邮箱正确");}
else//不正确清空
{document.getElementById('mail').value="";}
}
</script>