Question

Such code works for Label:

function doGet() {
 var app = UiApp.createApplication().setStandardsMode(true);
 return app.add(app.createLabel('centered').setStyleAttributes(
     {marginLeft: 'auto',
      marginRight: 'auto',
      width: '100px'}));
}

But it for button it doesn’t work. It doesn’t center the button. Why and how make it works?

Answer 1

Try adding display:block to the styles

Just to add: these aren’t Apps Script specific hacks per se… this is just standard CSS. You can use the Mozilla Developer Network as a resource for learning more about how different elements react to different CSS.

Also, all Gui Builder components have display:block implicitly set for them (that’s how it does the layouts).