How to conditionally load content (mobile-first) - mobile

Question

I am about to create my first 'mobile-first' website and am unsure on the best way to conditionally load content as the viewport increases.
For example, lets say I wish to load a twitter feed only for desktop browsers, not mobile, how would I do this?
Option 1) Display: none - This is bad as content still loads for mobile
Option 2) Have content in markup, but remove.element with javascript - I believe this content still loads first, then is removed after? If so, not good.
Option 3) Using javascript, if viewport is wide enough, load content - This seems to be the recommended approach, from what i've read, but Is it a good idea to have markup in javascript? I am thinking about accessibility, semantics and seo.
Are there any other better solutions?
Any advice would be greatly appreciated.

Answer 1

You might want to check out Modernizr . It's easy to install and you can use it check for HTML5 support in a visitors browser, as well as the window width, for example:
if (Modernizr.mq('(min-width: 400px)')) {
/* do this for tablets and desktops */
}else{
/* do this for handhelds */
}
Good luck!
UPDATE
thanks, but then in that case would it not be better to do that straight with javascript - if (document.documentElement.clientWidth > 640)
You are right, for that specific instance of deciding whether or not to load a twitter feed, there probably isn't a big advantage of using my suggestion over your option 3. Thinking ahead though, with repsonsive design, mobile sites and now HTML5, the next questions you are going to come up against are how to customise the CSS for different viewpoints, or how to test if a visitor's browser supports a certain HTML5 feature.
You could certainly take a roll-your-own approach and write custom javascript for each case, or you could use Modernizr to test if the visitors browswer supports media queries, and if it doesn't load respond.js, or use Modernizr to test if the vistor's browser supports geolocation or html5 forms or certain video formats ..., and if it doesn't conditionally load a cross browser polyfill.
There are usually multiple ways of achieving the same goal, I'm strong on not reinventing the wheel ;)

Answer 2

Who says? Display:none; is one the best practices in showing and hiding elements for any specific viewport.
And one thing Adam, mark-up is the least downloadable stuff for each device, they have to process some other things if you hide element by Jquery or Javascript. Because sometimes small devices either don't support loading them or take extra time that's why they are visible.
But it has the pitfall for SEO purposes.
For SEO optimization along with hiding elements you can do one of these things with your CSS.
First,
#media screen and (max-width:480px) {
div {
position: absolute;
left: -9999em;
width: 0;
height: 0;
overflow: hidden;
}
}
But it was the less efective because Google Webmaster takes care all such hacks. And You may be blacklisted from being Google indexed.So You should use one of these modern methods to hide elements.
Second,
div {
position: absolute !important;
clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
padding: 0 !important;
border: 0 !important;
height: 1px !important;
width: 1px !important;
overflow: hidden;
}
or, third,
div {
color:transparent;
text-indent:100%;
overflow:hidden;
white-space:no-wrap;
font:0/0 a;
text-shadow:none;
}