spaces.js

SomeClass({
  handleRequest: function () {
    ajax({
      onSuccess: function (req) {
        if (req.status == 'error') return;
        // Blah
      }
    });
  }
});

tabs.js

SomeClass({
	handleRequest: function () {
		ajax({
			onSuccess: function (req) {
				if (req.status == 'error') return;
				else {
					// Blah
				}
      			}
    		});
  	}
});