Changing UVs

I’m attempting to change UVs of an object loaded from a blender scene. I based my code on another example that works with three.js.

blender scene

https://jsfiddle.net/9xy4k1o0/

var obj = app.scene.getObjectByName(VARS['object']);

if (obj.hasOwnProperty('geometry')) 
{
    var UVatribs = obj.geometry.getAttribute("uv"); 
    // Modify UV map			
    for (var i = 0; i < UVatribs.count; i++) 
    {
        
        var u = UVatribs.getX(i);
        var v = UVatribs.getY(i);
        
        // do something with uv
        u = Math.random();
        v = Math.random();
            
        // write new values to attribs
        UVatribs.setXY(i, u, v);
    }
    UVatribs.needsUpdate = true;
    
    obj.geometry.setAttribute("uv", UVatribs);
}