Adjust tracking (character spacing) of selected text

I am looking for a script that will allow me to apply a specific tracking value to selected text in InDesign. I'm not even an amateur in scripting.

I found the following script in the referenced article: Script:  Adjust tracking (character spacing) of text

/*

<javascriptresource>

<name>Character Tracking...</name>

<enableinfo>true</enableinfo>

<menu>automate</menu>

<about>Adjust the kerning.</about>

<category>Typography</category>

</javascriptresource>

*/

if (app.documents.length > 0) {

    var targettext = app.activeDocument.activeLayer.textItem;

    targettext.tracking = parseInt(prompt("Select the tracking value", 0));

}

This looks like it's approximately what I would like to do. Two problems, I think it is just designed for Photoshop(?), and secondly, I want to use it for only selected text, not the entire page. Also,I would like to apply the script to a keyboard shortcut (I assume that's possible).

Can anyone assist in this? Sorry to ask, but I've got a large two-column document with large amounts of tracking to do and looking for shortcuts for clicking or typing in the tracking drop-down box.

Many thanks!