function validate(field) {
var ValidChar="1234567890/"
var ok = "yes";
if (field.value <= 0 )
{ ok = "yes";}
else
{
	var MyStr=field.value.substring(field.value.length-1,field.value.length);
	if (ValidChar.indexOf(MyStr)==-1)
		{ok = "no";}
}
if (ok == "no") {
	alert("Invalid entry. Only order number formats are accepted");
	field.value=(field.value.substring(0,field.value.length-1));
	if (field.value==""){
		field.value=1; }
		field.focus();
		field.select();	
   	}
}