function checkIfValid(checkStr,str){
	
  var checkOK = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
  var found;

   for (i = 0;  i < checkStr.length;  i++){
        ch = checkStr.charAt(i);
	    found=0;
         for (j = 0;  j < checkOK.length;  j++){
		   if (ch == checkOK.charAt(j)){
             found ++;
		   }
		}
		   
	if (found == 0){
		alert("Please enter only digit/alphabets in the \"" + str + "\"  field.");
        return false;
	 }

   }
  return true;
}