function isEml(str) { 
// are regular expressions supported? 
   var supported = 0; 
   if (window.RegExp)  
   { 
      var tempStr = "a"; 
      var tempReg = new RegExp(tempStr); 
      if (tempReg.test(tempStr)) supported = 1; 
   } 
   if (!supported) return (str.indexOf(".") > 2) && (str.indexOf("@") > 0); 
 
   var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)"); 
   var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$"); 
   return (!r1.test(str) && r2.test(str)); 
}