js 实现全选和反选

js代码

<script type="text/javascript">function selectAll() {var elements = document.getElementsByTagName('input');var ch = document.getElementById("allselect_top");if (ch.checked) {/*  全选 */for ( var i = 0; i < elements.length; i++) {if (elements[i].type == 'checkbox') {if (elements[i].checked == false) {elements[i].checked = true;}}}}else{  /* 反选 */for ( var i = 0; i < elements.length; i++) {if (elements[i].type == 'checkbox') {if (elements[i].checked == true) {elements[i].checked = false;}}}}}</script>

 HTML代码

<input type="checkbox" id="allselect_top" class="ipc allselect" onclick="selectAll()">