<input type="button" name="haha" value="按钮" id="btn" /><input type="button" name="haha" value="按钮" id="Button1" /><input type="text" name="haha" value="按钮" id="Button2" />

    <script type="text/javascript">        //1,根据获取单个该元素        var btnObj = document.getElementById(‘btn‘);        //2,根据name获取所有name属性一样的元素        var objs = document.getElementsByName(‘haha‘);        for (var i = 0; i < objs.length; i++) {            alert(objs[i].id);//每个元素的id        }        //3,根据标签,获取元素        var inputs = document.getElementsByTagName(‘input‘);        for (var i = 0; i < inputs.length; i++) {            if (inputs[i].type == ‘text‘) {                inputs[i].value = ‘哈哈哈我是文本框‘;            }        }    </script>