如何使用javascript更改DOM元素，具体取决于客户端的屏幕大小

I am working on this event slider which has 3 posts with left, right scroll buttons. but i am new to responsive designs, and i want to change the whole content including all the elements in the DIV once the screen size reduces to 1000px. please help me with some ideas to go through.I am working on this event slider which has 3 p