<h2>Active JavaScript Just in Mobile</h2>
<div class="box"></div>
.box {
width: 250px;
height: 200px;
}
if($(window).width()<600){
$(".box").css("background", "red");
}else{
$(".box").css("background", "black");
}
// this is used whenever the window is resized
$(window).resize(function(){
if($(window).width()<600){
$(".box").css("background", "red");
}else{
$(".box").css("background", "black");
}
});
HTML
CSS
JS