How to display native alert in Adobe Premiere pro extension

Hi i want to always show the native alert but when i do it in Javascript side it will look like this as shown below

In MAC it even looks even Ugly

the above alert comes when i do something like this from Javascript side

alert('Are you sure to delete')

When i do it in jsx side , it will look something like shown below

JSX side

alert('No active sequence');

Question: i always want to display native alert even from javascript side how can i achieve that