How can I let a user download multiple files when a button is clicked?

How can I let a user download multiple files when a button is clicked?

So I have a httpd server running which has links to a bunch of files. Lets
say the user selects three files from a file list to download and they're
located at:
mysite.com/file1 mysite.com/file2 mysite.com/file3
When they click the download button I want them to download these three
files from the links above.
My download button looks something like:
var downloadButton = new Ext.Button({
text: "Download",
handler: function(){
//download the three files here
}
});