function check(object) { var s =document.getElementById(object.id).value; var pattern =/^[a-zA-Z0-9_/-]{1,}@[a-zA-Z0-9_/-]{1,}/.[a-zA-Z0-9_/-.]{1,}$/; if(s!="") {alert("1"); if(!pattern.exec(s)) {alert("2"); alert('请输入正确的邮箱地址'); object.value=""; object.focus(); } } }