Tag Archives: reflow

jQuery cssText Helps You Improve Browser Reflows

cssText

You know you can manage to redraw an element with single browser reflow. Instead of using .style.property … you can simply add all CSS properties you’d like to change with simply appending to style.cssText property.

var csstxt = $('#selector').css('cssText') + ';top:100;left:100;border:1px solid red;color:#f00;';
$('#selector').css('cssText', csstxt);

That code is a replacement for

$('#selector').css({
   left : '100px',
   top : '100px',
   border : '1px solid red',
   color : '#f00'
});

enjoy!

jQuery CSS selectors. Change one or more CSS properties!

Browser reflows and performance issues

What is a browser reflow? Well actually when you change some property in CSS like change of a color, width, height, font-size, etc. normally the browser redraws the layout just to fit the new requirements after the reflow.

The problem is not in the first render of the page. Than the CSS is just parsed and everything is positioned as the browser reads the CSS. The problem is when you change some CSS property using JavaScript, and in our case using jQuery.

In fact nowadays is very popular to make every kind of animation using JavaScript and most of the “big” libraries, such as jQuery, give you a built in set of functions just to make this task easier for you. Continue reading jQuery CSS selectors. Change one or more CSS properties!