Problems w/ Dynamic Text Field calling ASP file

My sincere apologies if this thread seems simple but for me, an Action Script 2.0 newbie-- I am really struggling.

I have a Dynamic Text Field that is calling an external HTML file with no problem at all – but I need it to call a (.asp) file into this text box from an external server …

What code would I place in the Text Field MC to have it call a URL (.asp) into the box and display?

Thank you, Thank you, Thank you!
Any help muchly appreciated !!!