How to use javascript conditionally like CSS3 media queries, orientation?

You can use window.matchMedia():

Test a mobile device media query

if (matchMedia('only screen and (max-width: 480px)').matches) {  // smartphone/iphone... maybe run some small-screen related dom scripting?}

Test landscape orientation

if (matchMedia('all and (orientation:landscape)').matches) {  // probably tablet in widescreen view}

Currently supported in all modern browsers (more details)

Polyfill for old browsers: https://github.com/paulirish/matchMedia.js/

...I want to run a javascript only if max-width of browser is 1900px and min-width is 768

EDIT: Actually, that was all wrong. If you're using a mobile device, use:

function doStuff(){    landscape = window.orientation? window.orientation=='landscape' : true;    if(landscape && window.innerWidth<1900 && window.innerWidth > 768){        //code here    }}window.onload=window.onresize=doStuff;if(window.onorientationchange){    window.onorientationchange=doStuff;}

I can think of a quick solution: Apply some styles conditionally to an invisible div, and check if they are applied with javascript:

div#test { display: none }@media only screen and (width : 1024px) and (orientation : landscape) {    div#test { background-color: white; }}

if(document.getElementById('test').style.backgroundColor == 'white')    mediaSelectorIsActive();