"is owner logged in check, switch" (SOLVED)

If #input2 is connected to a dataset that is tied to Database2, you need a dataset onReady statement too.

$w.onReady(function () {
    $w("#dataset2").onReady( () => {
         let value1 = $w("#input1").value;
         let value2 = $w("#input2").value;
         if ( value1 === value2) {
            $w("#updatebutton").show();  //do this thing
         } else {
            $w("#updatebutton").hide();  //or else do this 
         }
    });
});