js实现的类似QQ的等级的代码

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 
<html> 
    <head> 
        <meta http-equiv="Content-Type" content="text/html; charset=GB2312" /> 
        <title>类似QQ等级</title> 
        <script type="text/javascript"> 
        function $(obj){ 
            return document.getElementById(obj); 
        } 
        function checkIsInteger(str){ 
             if(str == "") 
         return false; 
         if(/^(\-?)(\d+)$/.test(str)) 
return true; 
else 
return false; 
} 
         function t(num){ 
             var str = ""; 
            var sun = Math.floor(num/640); 
            for(var i = 0;i < sun;i++) 
                str += "●"; 
            var month = Math.floor(num/160)%4; 
            for(var j = 0;j < month;j++) 
                str += "?"; 
            var star = Math.floor(num/40)%4; 
            for(var k = 0;k < star;k ++) 
                str += "★"; 
            window.alert(str); 
             
         } 
         String.prototype.trim = function(){ 
             return this.replace(/(^[\s]*)|([\s]*$)/g, ""); 
     } 
         window.onload = function(){ 
             $("btn").onclick = function(){         
                if(checkIsInteger($("txt").value.trim())){ 
                    t($("txt").value.trim()); 
                }else{ 
                    alert("只能是数字"); 
                } 
             } 
         } 
        </ script> 
    </head> 
    <body> 
        <input type="text" id="txt" /> 
        <input type="button" value="Go" id="btn" /> 
    </body> 
</html>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

js实现的类似QQ的等级的代码_javascript技巧