Maintains aspect ratio as (jQuery plugin)

maintain_aspect.js

    $.fn.maintainAspect = function(cb){ 
        var el = this,
        _maintain_aspect = function(el){
            var $width = el.parent().width();
            var $height = $width / 2.39;
            
            el.attr('width', $width)
            el.attr('height', $height)

            //trigger callback
            cb()
        };

        // initialize
        _maintain_aspect(el)

        $(window).resize(function(){
            _maintain_aspect(el)
        })

        
    }