Repeatedly reduce the width of a div

Question

I need the width of a specific <div> to get smaller by 50px every time a JavaScript function is called.

I tried

document.getElementById("Zivot").style.width = "100px";

But that just sets the width, and doesn't add or subtract it.

Answer 1

Use this code. Get the width using offsetWidth and reduce it by 50px every time.

var element = document.getElementById('Zivot'); 
element.style.width = (element.offsetWidth - 50) + 'px';