// Preload animation images

function checkQuantity() {
    
    var quantity = document.getElementById('quantity');
    
    if (parseInt(quantity.value) <= 0 || isNaN(quantity.value)) {
        alert("Quantity must be a number greater than 0");
        quantity.focus();
        return false;
        
    }
    
 
   
}

function checkShipping() {
    
   var shipping_select = document.getElementById('shipping_pulldown');
   var selected_index = shipping_select.selectedIndex; 
   
   if (shipping_select.options[selected_index].value == '') {
        alert("You must select a shipping method");
        shipping_select.focus();
        return false;
   } 

}

function popUp(URL) {

var centerWidth = (window.screen.width - 400) / 2;
var centerHeight = (window.screen.height - 350) / 2;

day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=400,height=350,left = " + centerWidth + ",top = " + centerHeight + "');");
}