JavaScript: Modernizr & jQuery placeholder replacement

modernizr_jquery_placeholder_fix.js

if(!Modernizr.input.placeholder){
                $('input[type=text]').each(function(i, elem) {
                var input = $(elem),
                    placeholder = input.attr('placeholder');
                if (this.defaultValue === '') {
                        this.defaultValue = placeholder;
                }
                input.on('focus', function () {
                    this.value == this.defaultValue ? this.value = '' : null;
                })
                .on('blur', function () {
                    !this.value.length ? this.value = this.defaultValue : null;
                }).blur();
   });
}