function isEmail(str) {
  var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
    return (filter.test(str));
 }
 
 function checkForm() {
  var frm  = document.forms[0];
  var name = frm.NAME.value;
  var email= frm.EMAIL.value;
 
  if(name.length<=2 || name=='') {
   alert('Please provide a valid name');
   frm.NAME.focus();
   return false;
  } 
  else if(!isEmail(email)) {
   alert('Please provide a valid email');
   frm.EMAIL.focus();
   return false;
  } 
  else {
   return true;
  }

 }