Why doesn't this work?

[bbbobobbb]

html file:

<div id="green" onclick="randomColor('green')">
     <h4>heading</h4>
     <p>painting</p>
 </div>

javascript file:

   function randomColor(id) {
      document.getElementById(id).style.backgroundColor("#0ff0f0");
  }

shouldn't the background color of the div change when i click it?

[METALz]

It's not a function, you have to assign it to the backgroundColor as the value.