// JScript File
function Demo()
{debugger;
  var myVal = document.getElementById('RegularExpressionValidator1');
  var myVal1 = document.getElementById('RequiredFieldValidator2');
  var x=document.forms["form1"]["TxtEmailid"].value;
        var atpos=x.indexOf("@");
        var dotpos=x.lastIndexOf(".");
                        if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
                           {
                            ValidatorEnable(myVal, true); 
                           }
                        else
                           {
                            ValidatorEnable(myVal, false); 
                           }
}