var messageBox='msgBox';
function checkQuantity(){ // validating quantity before update
	var frm=document.cartFrm;
	var limit=frm.elements.length;
	var foc=-1;
	for(i=0;i<limit;i++){
		if(frm.elements[i].type=="text"){
			if(isNaN(frm.elements[i].value)){
				if(foc==-1)foc=i;	
				frm.elements[i].className="inputError";						
			}
			else frm.elements[i].className="inputNormal";						
		}
	}
	if(foc!=-1){
		var msgBox=document.getElementById(messageBox);
		msg='<ul><li>'+quantityErr+'</li></ul>';
		msgBox.style.display="";
		msgBox.innerHTML=msg;
		frm.elements[foc].focus();
		return false;
	}
	return true;;
}