.html代码如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>

<head>
<style type="text/css">
  #show{
    width:100px;
    height:100px;
    margin:0 auto;
    background:#2c2c2c;
    color:#fff;
    text-align:center;
  }
</style>

<title>进制转换</title>
<script type="text/javascript">
  document.write("<div id='show'>");
  var data = parseInt(prompt("请输入十进制数据",1));//注意prompt函数
  var base = parseInt(prompt("请输入进制基数(2,8,16)",2));
  var result ;
  switch(base){
    case 2 : 
    case 8:
    case 16 : result = data.toString(base);break;
    default : result = "<span style='color:red'>非法</span>";
    
  }
  document.write(result);
  documeng.write("</div>");
</script>
</head>
<body>
</body>
</html>

效果如下：

javascript小练习之进制转换_javascript

javascript小练习之进制转换_html_02

javascript小练习之进制转换_html_03