src/attributes/support.js

define( [

    "../var/document",

    "../var/support"

], function( document, support ) {

"use strict";

( function() {

    var input = document.createElement( "input" ),

        select = document.createElement( "select" ),

        opt = select.appendChild( document.createElement( "option" ) );

    input.type = "checkbox";

    // Support: Android <=4.3 only

    // Default value for a checkbox should be "on"

    support.checkOn = input.value !== "";

    // Support: IE <=11 only

    // Must access selectedIndex to make default options select

    support.optSelected = opt.selected;

    // Support: IE <=11 only

    // An input loses its value after becoming a radio

    input = document.createElement( "input" );

    input.value = "t";

    input.type = "radio";

    support.radioValue = input.value === "t";

} )();

return support;

} );