Chrome/Safari POST Issues - post

Question

I wrote a small shopping cart in .Net that sends someone to PayPal upon order completion to make payment. To send them to PayPal I have the following form on a generic "paypal.aspx" page that has no real user functionality on it:
<form action="http://www.paypal.com/cgi-bin/webscr" method="post" id="paypal">
<input type="hidden" name="cmd" value="_cart"/>
<input type="hidden" name="upload" value="1"/>
<input type="hidden" name="business" value="email#email.com"/>
<input type="hidden" name="tax_cart" id="tax_cart" />
<input type="hidden" name="handling_cart" id="handling_cart" />
<input type="hidden" name="return" id="return" value='<%="http://" + Request.Url.Authority + "/" %>' />
<input type="hidden" name="custom" id="custom" />
<input type="hidden" name="first_name" id="first_name" />
<input type="hidden" name="last_name" id="last_name" />
<input type="hidden" name="address1" id="address1" />
<input type="hidden" name="address2" id="address2" />
<input type="hidden" name="city" id="city" />
<input type="hidden" name="state" id="state" />
<input type="hidden" name="zip" id="zip" />
<input type="submit" id="paypalButton" value="PayPal" style="display: none; visibility: hidden;"/>
</form>
When the page containing this form loads, there is another form directly below it with a bunch of hidden fields that are filled in with data from the actual order (which is pulled based on a Guid query string value). The JavaScript in that form fills in the values that PayPal requires like this:
<form runat="server">
<asp:ScriptManager runat="server" />
<div id="ppItems">
<asp:Repeater runat="server" ID="rpItems">
<ItemTemplate>
<input type="hidden" id='<%#"hv_quantity_" + Container.ItemIndex %>' value='<%#Eval("Quantity") %>' />
<input type="hidden" id='<%#"hv_item_" + Container.ItemIndex %>' value='<%#Eval("Color") + " Tactical Hat" %>' />
<input type="hidden" id='<%#"hv_amount_" + Container.ItemIndex %>' value='<%#Eval("UnitCost", "{0:n2}") %>' />
</ItemTemplate>
</asp:Repeater>
</div>
<asp:HiddenField runat="server" ID="hvCustom" />
<asp:HiddenField runat="server" ID="hvTax" />
<asp:HiddenField runat="server" ID="hvShipping" />
<asp:HiddenField runat="server" ID="hvFirstName" />
<asp:HiddenField runat="server" ID="hvLastName" />
<asp:HiddenField runat="server" ID="hvAddress1" />
<asp:HiddenField runat="server" ID="hvAddress2" />
<asp:HiddenField runat="server" ID="hvCity" />
<asp:HiddenField runat="server" ID="hvState" />
<asp:HiddenField runat="server" ID="hvZip" />
<script type="text/javascript" language="javascript">
var paypal = document.getElementById('paypal');
function load() {
Sys.Application.remove_load(load);
//set the items
var ppItems = document.getElementById('ppItems');
var items = ppItems.getElementsByTagName('input');
var itemsCount = items.length / 3;
for (var i = 0; i < itemsCount; ++i) {
var quantity = document.getElementById('hv_quantity_' + i).value;
var item = document.getElementById('hv_item_' + i).value;
var amount = document.getElementById('hv_amount_' + i).value;
addFormItem('item_name_' + (i + 1), quantity + " " + item);
addFormItem('amount_' + (i + 1), amount);
addFormItem('quantity_' + (i + 1), quantity);
}
//set global items
var custom = document.getElementById('<%=this.hvCustom.ClientID %>').value;
document.getElementById('tax_cart').value = document.getElementById('<%=hvTax.ClientID %>').value;
document.getElementById('handling_cart').value = document.getElementById('<%=this.hvShipping.ClientID %>').value;
document.getElementById('return').value += 'thanks.aspx?p=' + custom;
document.getElementById('custom').value = custom;
document.getElementById('first_name').value = document.getElementById('<%=this.hvFirstName.ClientID %>').value;
document.getElementById('last_name').value = document.getElementById('<%=this.hvLastName.ClientID %>').value;
document.getElementById('address1').value = document.getElementById('<%=this.hvAddress1.ClientID %>').value;
document.getElementById('address2').value = document.getElementById('<%=this.hvAddress2.ClientID %>').value;
document.getElementById('city').value = document.getElementById('<%=this.hvCity.ClientID %>').value;
document.getElementById('state').value = document.getElementById('<%=this.hvState.ClientID %>').value;
document.getElementById('zip').value = document.getElementById('<%=this.hvZip.ClientID %>').value;
//submit to paypal
document.getElementById('paypalButton').click();
}
function addFormItem(name, value) {
var item = document.createElement('input');
item.setAttribute('type', 'hidden');
item.setAttribute('name', name);
item.setAttribute('id', name);
item.setAttribute('value', value);
paypal.appendChild(item);
}
Sys.Application.add_load(load);
</script>
So when this overall page loads, order detail is pulled from the database based on the query string guid value, a bunch of hidden fields are filled with the required values from the database and then the above script runs on load setting the PayPal form values and then clicking the hidden button submits everything to PayPal so the end user can pay.
The issue I have is this works great in IE7+ and FF3+, but Safari and Chrome are not playing nicely. In Chrome I get redirected to the PayPal home page instead of being asked to pay. Safari is even stranger in that both redirect to the PayPal payment screen (like IE7+ and FF3+), but on the Mac version only it doesn't pre-populate all the fields (specifically name/address), but other fields (such as amount, tax, etc.) do populate.
Can anyone provide any suggestions as to why Chrome and Safari (Mac only) don't work right, but everything else seems to?

Answer 1

I finally figured it out by going the old school route and redirecting instead of executing a POST:
var order = (from o in data.Orders where o.PayPal == Request.QueryString["p"] select o).Single();
//build the generic PP detail
sb.Append("http://www.paypal.com/cgi-bin/webscr/?cmd=_cart");
sb.AppendValue("upload", "1", false);
sb.AppendValue("business", "email#domain.com", true);
sb.AppendValue("handling_cart", (this.CurrentCart.Tax.HasValue ? this.CurrentCart.Tax.ToString() : "0"), false);
sb.AppendValue("return", this.Request.Url.Authority, true);
sb.AppendValue("custom", order.PayPal, true);
sb.AppendValue("first_name", (order.Customer.Name.IndexOf(" ") > -1) ? order.Customer.Name.Split(' ')[0] : order.Customer.Name, true);
sb.AppendValue("last_name", (order.Customer.Name.IndexOf(" ") > -1) ? order.Customer.Name.Split(' ')[1] : order.Customer.Name, true);
sb.AppendValue("address1", order.Customer.Address1, true);
sb.AppendValue("address2", order.Customer.Address2, true);
sb.AppendValue("city", order.Customer.City, true);
sb.AppendValue("state", order.Customer.StateProvince, true);
sb.AppendValue("zip", order.Customer.PostalCode, true);
for (int i = 0; i < order.OrderItems.Count; ++i)
{
string index = (i + 1).ToString();
sb.AppendValue("item_name_" + index, order.OrderItems[i].ProductAttribute.Name, true);
sb.AppendValue("amount_" + index, string.Format("{0:n2}", order.OrderItems[i].UnitCost), false);
sb.AppendValue("quantity_" + index, order.OrderItems[i].Quantity.ToString(), true);
}
Response.Redirect(sb.ToString());
The AppendValue method is an extension method for a StringBuilder and it looks like this:
public static void AppendValue(this StringBuilder sb, string name, string value, bool encode)
{
sb.Append("&" + name + "=" + ((encode) ? HttpUtility.UrlEncode(value) : value));
}