How to hide/show elements based on Javascript

Sometimes you have a really great design with some really fancy Javascript goodness, like drag'n'drop and other shiny Ajaxy stuff.

But when you browse the website with Javascript disabled, none of that works and you end up with interface elements that should'nt be here because they do not work.

In those case, you'd rather display a nice message to your user, telling him that he can't use the feature withou Javascript enabled.

But how do you do that ?

Well, I myself load two different stylesheets. Remember that your website should be working without Javascript, this is just the last layer you add.

My default stylesheet will load all the rules for when Javascript is not enabled. No fancy cursor:move here.

Then I load a second stylesheet using Javascript, using document.write() in the <head>. And that's in this one that I write rules that overload the previous one. I add every styling that deals with Javascript-enabled features here.

Limitations

I may be changing the way I load the JS stylesheet in the future. I don't really like relying on document.write because it is evil. I also don't like the idea of getting one extra request.

I could add a js class to my body element (like modernizr does with all its CSS3 properties) and then target elements by prepending .js to the rule.

But it means adding rules in my main CSS file for users without JS that will still be downloading those extra useless bytes.

I haven't yet figured which way was the best (or should I say, the worst)

Convenient methodes

Whatever way you choose, one thing that really helped me was two real simple classes : jsOnand jsOffthat I add to elements.

Elements with jsOnwill only be visible if Javascript is enabled and hidden otherwise, while element with jsOffwill do the opposite.

Assuming you mark your body element with a js class if Javascript is enabled, here's how to do it :

.jsOn { display:none; }
.js .jsOn { display:block;
.jsOff { display:block;
.js .jsOff { display:none;

Hope all that helps at least someone.


Tags : #css #javascript #performance

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