How do I send users with screen sizes more than 700px to index.php from index.html and keep users with screen sizes less than 700px on the index.html ?
@deathshadowOct 11.2014 — #Why would you? We have something now called "responsive design" -- which mated to an elastic semi-fluid layout means you shouldn't even be THINKING about different markup for different screen sizes.
Rather than sending them to two different files, which is an accessibility train wreck and long term harder to maintain, use CSS3's media queries so that one markup can do two different layouts.
Which is why things like semantic markup, separation of presentation from content, elastic and semi-fluid design and so forth are important, so you aren't fighting an up-hlll battle when you go to make it responsive and have multiple different appearances from one set of markup and content.
@bsha100Oct 11.2014 — #You should be able to still implement a responsive design. You will need to add some classes to the markup, and edit the css for 'conditional' styling based on certain resolutions. The prevailing method today is '320 and up', which means you style from the lowest resolution up, and set breakpoints for certain resolutions ( i.e. for a minimum width of 960px, apply this style). Check out Bootstrap, that's my go-to and is really easy to use.