I'm working on a menu bar @ which initially which have a width property and when the screen size is less than 767(
@media screen and (max-width:767px)
767px
You don't necessarily need javascript if you only want to change the properties.
Write the styling of that class inside a media query e.g
@media screen and (min-width:768px){
// i am usign MIN-WIDTH:786px not MAX-WIDTH
.yourclass{
float: right;
}
}
So this property will be added to that element ONLY on screens greater than 786.