checkbox全选与取消
function checkall(){var userids = document.getElementsByName("check");if(userids.length==undefined){userids.checked=true;}else{for(var i=0;i<userids.length;i++){userids[i].checked=true;}document.getElementById("cid").innerHTML="<a href='javascript:cancelall()' style='text-decoration:none;'>[取消]</a>";}}function cancelall(){var userids = document.getElementsByName("check");if(userids.length==undefined){userids.checked=false;}else{for(var i=0;i<userids.length;i++){userids[i].checked=false;}document.getElementById("cid").innerHTML="<a href='javascript:checkall()' style='text-decoration:none;'>[全选]</a>";}}?