日期:2014-05-16  浏览次数:20392 次

如何用js判断一个复选框是否被选中?
<html> <head>
        <title>
            复选框全选、全不选、反选、必选一个
        </title>
        <meta http-equiv="content-type" content="text/html;charset=GBK"/>
        <script language="javascript">
            //表单验证
            function check(){              
                var ids = document.getElementsByName("ids");              
                var flag = false ;              
                for(var i=0;i<ids.length;i++){
                    if(ids[i].checked){
                        flag = true ;
                        break ;
                    }
                }
                if(!flag){
                    alert("请最少选择一项!");
                    return false ;
                }
            }
            //全选
            function iselect(){ //其中函数字不能为select 其为JS保留字
                var ids = document.getElementsByName("ids");
                var all = document.getElementByIdx_x_x("all");              
                for(var i=0;i<ids.length;i++){
                    ids[i].checked=all.checked;
                }
            }
            //全选
            function selectAll(){
                var ids = document.getElementsByName("ids");