تغيير لون الاستايل بضغطه واحده

#topbar {
height: 32px;
background: #CCCCCC;
}
.colorchooser {
float:right;
margin-right:10px;
margin-top:10px;
}

.colorchooser a {
  width:10px;
  height:10px;
  display:block;
  float:left;
  margin-left:5px
}

<link rel="alternate stylesheet" type="text/css" media="screen" title="orange-theme" href="orange.css" />
<link rel="alternate stylesheet" type="text/css" media="screen" title="violet-theme" href="violet.css" />
<link rel="alternate stylesheet" type="text/css" media="screen" title="red-theme" href="red.css" />
<link rel="alternate stylesheet" type="text/css" media="screen" title="grey-theme" href="grey.css" />
<link rel="alternate stylesheet" type="text/css" media="screen" title="black-theme" href="black.css" />
<link rel="alternate stylesheet" type="text/css" media="screen" title="pinkish-theme" href="pinkish.css" />
<script src="styleswitch.js" type="text/javascript"></script>
<div id="topbar">
<div class="colorchooser"> <span>try another  color  scheme: </span>
<a href="javascript:chooseStyle('orange-theme', 7)" style="background-color:#FF9900;"></a>
<a href="javascript:chooseStyle('violet-theme', 7)" style="background-color:#003366;"></a>
<a href="javascript:chooseStyle('red-theme', 7)" style="background-color:#990000;"></a>
<a href="javascript:chooseStyle('grey-theme', 7)" style="background-color:#999999;"></a>
<a href="javascript:chooseStyle('black-theme', 7)" style="background-color:#000000;"></a>
<a href="javascript:chooseStyle('pinkish-theme', 7)" style="background-color:#B26267;"></a> </div>
</div>