How to add disabled attribute to an element using Google Closure?

I am trying to disable an input field using Google Closure. Can anyone tell me what is the syntax for doing that operation using Google Closure?

Any element on google closure can be disabled using setAttribute() function.

/**
* @type {Element}
* @private
*/
this.$title_ = null; // call getElementByClass('','') here;
this.$title_.setAttribute('disabled', 'disabled');

Here this.$title is an input element.