window.onload = initAll;

function initAll(){
  for (var i=0; i<document.forms.length; i++){
      document.forms[i].onsubmit = function(){
	    return validForm();
	  }
  }
}

function validForm(){
   var allGood = true;
   var allTags = document.getElementsByTagName("*");
   
   for (var i=0; i<allTags.length; i++){
     if(!validTag(allTags[i])){
	    allGood = false;
	 }
   }
   
   return allGood;
   
   function validTag(thisTag){
      var outClass = "";
	  var allClass = thisTag.className.split(" ");
	  
	  for(var j=0; j<allClass.length; j++){
	     outClass += validBasedOnClass(allClass[j]) + " ";
	  }
   
       thisTag.className = outClass;
	   
	   if(outClass.indexOf("invalid") > -1){
	         thisTag.focus();
		 if(thisTag.nodeName == "INPUT"){
		    thisTag.select();
		 }
		 return false;
	   }
	   return true;
	   
	    function validBasedOnClass(thisClass){
          var classBack = "";
	   
	      switch(thisClass){
	           case "":
			   case "invalid":
			       break;
			   case "reqd":
			       if(allGood && thisTag.value == ""){
				      classBack = "invalid ";
					  }
					  classBack += thisClass;
					  break;
				default:
					  classBack += thisClass;
			}
			return classBack;
	   }
    }
  }