var toolbar = document.getElementById('toolbar');
if (!toolbar) { return false; }

var interval_id = setInterval( "checkToolbarLoaded()", 50 );
var interval_count = 0;
 
function checkToolbarLoaded() {
    if( interval_count == 100 ) {
        clearInterval( interval_id );
        throw "Failed to change the toolbar (timeout after 5 seconds)";
        return;
    } else if( getElementById( elementyouneed ) && getElementById( otherelementyouneed ) && etc ) {
//make your changes here.
    }
    interval_count++;
}