function hasFirstAPI () {
		if (!$.fn.jquery) return true; // for Zepto
		var versions = $.fn.jquery.split('.')
		return ( versions[0] !== '1' ||
			versions[0] === '1' && parseInt(versions[1], 10) >= 4 );
	}
Check whether .first() is existed

https://api.jquery.com/first/
https://api.jquery.com/first-selector/

use .first() when version is greater or equal to 1.4
@return {boolean}