js:全选&全不选 

<body>

 <input type="checkbox" name="fruit"  > 苹果<br>
 <input type="checkbox" name="fruit" > 香蕉<br>
 <input type="checkbox" name="fruit" > 火龙<br>
 <input type="checkbox" name="fruit" > 西瓜<br>
 
 <input type="button" id="btn"  value="全选"  onclick="bb()">

</body>

<script type="text/javascript">

function bb(){
    var btn1 = document.getElementById("btn");
    var fruits = document.getElementsByName("fruit");
    
    
    if(btn1.value=="全选")
        for (var i = 0; i < fruits.length; i++) {
            fruits[i].checked=true;
            btn1.value="全不选";
        }else if(btn1.value=="全不选")
        for (var i = 0; i < fruits.length; i++) {
            fruits[i].checked = false;
            btn1.value="全选";
        }
    
}


</script>

ckeckbox形式的全选和全不选

function check1(){
    
    var fruits = document.getElementsByName("fruit");
    var ch = document.getElementById("btnn");
        for (var i = 0; i < fruits.length; i++) {
            fruits[i].checked=ch.checked;
        }
    
    }

 

特别注意: 必须是if...else if....     如果是if...if...就会出问题

posted @ 2016-08-19 16:59  乱世_独自美  阅读(91)  评论(0)    收藏  举报