var isSubmit=false;
	  function dingdan_en(obj)
      {
         if (isSubmit) return false;
		 var flag=false;
         var fm=obj;
         var mustfill=new Array("dd1","dd2","dd4","dd6");
         for (var i=0;i<mustfill.length;i++)
         {
             fm[mustfill[i]].value=trim(fm[mustfill[i]].value);
             if (fm[mustfill[i]].value==""){
                alert("Please fill Completely!");
                fm[mustfill[i]].focus();
                return false;
            }
         }
         
         if (fm["dd6"].value!=""){
             if (!isemail(fm["dd6"].value)){
                alert("Invalidated E-mail!");
                fm["dd6"].focus();
                return false;
             }
         }
         if (/^[\+\-\d]{5,}$/.test(fm["dd4"].value)==false){
             alert("Invalidated Telephone!");
            fm["dd4"].focus();
            return false;
         }
		 isSubmit=true;
      }