Random div color

HTML

<div id="container">
  <div id="color-div">
  </div>
</div>

CSS

#color-div{
  border:1px solid gray;
  width:50px;
  height:50px;
}

JavaScript

$(document).ready(function(){ 
  var colors = ['red','blue','#123123','#FF765443'];
  var new_color = colors[Math.floor(Math.random()*colors.length)];
  $('#color-div').css('background-color',new_color);
});