get current text frame width in indesign script

Question

the below code gets the first text frame width in my doc. How can I get the active text frame Width in Indesign script? The image shows my problem.

function freamWidth() {

    var frameRef = app.documents[0].textFrames[0];
    var gBounds = frameRef.geometricBounds;
    var y0 = gBounds[0];
    var x0 = gBounds[1];
    var y1 = gBounds[2];
    var x1 = gBounds[3];
    //do calculations
    var frameWid = x1 - x0;
 //   var frameHgt = y1 - y0;
    return frameWid;
}

Answer 1

This is more a question of how to retreive the parent text frame of a selection. You can usually do this via the parentTextFrames property of a text selection. You could optionally also include a check if the text frame itself is selected instead of some text within the text frame. So the following code should work for your scenario:

var tf;
var sel = app.selection[0];

if(sel.hasOwnProperty('baseline')) {
  tf = sel.parentTextFrames[0];
} else if (sel instanceof TextFrame) {
  tf = sel;
}

var tfWidth = tf.geometricBounds[3] - tf.geometricBounds[1];

alert("The text frame width is " +  tfWidth);