JavaScript全选、反选复选按钮的实现代码

  <script language="javascript"> 
    function checkAll(form1,status){             
        var elements = form1.getElementsByTagName('input'); 
        for(var i=0; i<elements.length; i++){ 
            if(elements[i].type == 'checkbox'){ 
                if(elements[i].checked==false){ 
                    elements[i].checked=true; 
                } 
            } 
        }    
    } 
    function switchAll(form1,status){            
        var elements = form1.getElementsByTagName('input'); 
        for(var i=0; i<elements.length; i++){ 
            if(elements[i].type == 'checkbox'){ 
                if(elements[i].checked==true){ 
                    elements[i].checked=false; 
                }else if(elements[i].checked==false){ 
                    elements[i].checked=true; 
                } 
            } 
        }    
    } 
    function uncheckAll(form1,status){   
        var elements = form1.getElementsByTagName('input');      
        for(var i=0; i<elements.length; i++){                    
            if(elements[i].type == 'checkbox'){              
                if(elements[i].checked==true){                   
                    elements[i].checked=false;                   
                } 
            } 
        }    
    } //edit www.jb200.com
    </script>

<tr>
    <td colspan="12" align="center">
    <img src="images/check.jpg" onclick="checkAll(form1,status);" />         
    <img src="images/switch.jpg" onclick="switchAll(form1,status);" />        
    <img src="images/uncheck.jpg" onclick="uncheckAll(form1,status);" />
    </td>
    </tr>