var str_txt_pro350 = "";
var str_txt_pro500 = "";
var str_txt_pro1500 = "";
var str_txt_pro20 = "";

function submit_order(){	
	var pro350 = document.getElementById('txt_pro350');
	var pro500 = document.getElementById('txt_pro500');
	var pro1500 = document.getElementById('txt_pro1500');
	var pro20 = document.getElementById('txt_pro20');
	
	str_txt_pro350 = (check_quantity(pro350)== true)?"":"error";
	str_txt_pro500 = (check_quantity(pro500)== true)?"":"error";
	str_txt_pro1500 = (check_quantity(pro1500)== true)?"":"error";
	str_txt_pro20 = (check_quantity(pro20)== true)?"":"error";
	
	if(pro350.value != "" || pro500.value != "" || pro1500.value != ""  || pro20.value !=""){
		if(str_txt_pro350 != "" || str_txt_pro500 != "" || str_txt_pro1500 != ""  || str_txt_pro20 !="" ){
			return false;
		}else{
			return true;
		}
	}else{
		return false;
	}	
}

function check_quantity(obj){
	
	if(obj.value !=""){
		if(isNaN(obj.value)){
			document.getElementById('img_' + obj.id).innerHTML="<img src='images/icon_cross.gif'/>";
			return false;
		}else{
			document.getElementById('img_' + obj.id).innerHTML="";
			return true;
		}
	}else{
		document.getElementById('img_' + obj.id).innerHTML="";
			return true;
	}
}