js进击--一些常用小方法

1. 获取当前日期

   <script type="text/javascript">
   var mydate=new Date();
   var weekday=["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
   var today = mydate.getDay();
   document.write("今天是：" + weekday[today]);
   </script>

2. 当前时间推出两小时

   <script type="text/javascript">
   var mydate=new Date();
   document.write("当前时间："+mydate+"<br>");
   mydate.setTime( mydate.getTime() + 2* 60 * 60 * 1000);
   document.write("推迟二小时时间：" + mydate);
   </script>

3. 降序排列数组

   <script type="text/javascript">
   function sortNum(a,b) {
       return b-a;
   }
   var myarr = new Array("80","16","50","6","100","1");
   document.write(myarr.sort(sortNum));
   </script>

4. 判断浏览器

function validB(){ 
    var u_agent = navigator.userAgent; 
    var B_name="非主流浏览器!"; 
    if(u_agent.indexOf("Firefox")>-1){ 
        B_name="Firefox"; 
    }else if(u_agent.indexOf("Chrome")>-1){ 
        B_name="Chrome"; 
    }else if(u_agent.indexOf("MSIE")>-1&&u_agent.indexOf("Trident")>-1){ 
        B_name="IE(8-10)";  
    }
        document.write("浏览器:"+B_name+"<br>");
        document.write("u_agent:"+u_agent+"<br>"); 
  } 

1. 计数器

<label id="txt1"></label>
<script type="text/javascript"> 
    var num=0;
    function count()
    {
        document.getElementById("txt1").innerHTML=num;
        num = num +1;
        setTimeout("count()",1000);
    }
    count();
</script> 

删除某节点下的元素

function clearText() {
        var content=document.getElementById("content");
        var childCount = content.childNodes;
        // 在此完成该函数
        for(var i=childCount.length-1;i>=0;i--)
        {
            content.removeChild(content.childNodes[i]);
        }

    }