怎样能在提交表单时过滤掉没更改的值，只POST修改过的值？
假如有个网站配置的表单里面有超过二十个的值，有时候只更改了一两个值，如果全部POST的话来更新的话会造成效率很低，能不能在提交时就判断，如果没更改过的值就不提交了？javascript和jquery都略懂一点
[解决办法]
估计你想要的功能应该是这样的
<script type="text/javascript">function IsFormChanged(el,radios) { var isChanged=""; var form = document.getElementById(el); for (var i = 0; i < form.elements.length; i++) { var element = form.elements[i]; var type = element.type; switch(type){ case "text": case "hidden": case "textarea": case "button": isChanged += (element.value != element.defaultValue)?isChanged.length==0?element.name+"="+element.value:"&"+element.name+"="+element.value:""; break; case "checkbox": isChanged += (element.checked != element.defaultChecked)?isChanged.length==0?element.name+"="+element.value:"&"+element.name+"="+element.value:""; break; case "select-one": case "select-multiple": for (var j = 0; j < element.options.length; j++) { isChanged += (element.options[j].selected != element.options[j].defaultSelected)?isChanged.length==0?element.name+"="+element.value:"&"+element.name+"="+element.value:""; } break; } } var radiolist=radios.split(','); for(var j=0;j<radiolist.length;j++){ var myRadio=document.getElementsByName(radiolist[j]); for(var k=0;k<myRadio.length;k++){ isChanged += (myRadio[k].checked && !myRadio[k].defaultChecked)?isChanged.length==0?myRadio[k].name+"="+myRadio[k].value:"&"+myRadio[k].name+"="+myRadio[k].value:""; } } alert(isChanged); } </script><form id="chageform"> <input type="checkbox" name="myBox" value="1"/> <input type="checkbox" name="myBox" value="2"/> <input type="checkbox" name="myBox" value="3"/><br /> <input type="radio" name="myRadio" checked="checked" value="1"/> <input type="radio" name="myRadio" value="2"/><br /> <input type="radio" name="myRadio2" value="1"/> <input type="radio" name="myRadio2" checked="checked" value="2"/><input type="button" value="检测" onclick="IsFormChanged('chageform','myRadio,myRadio2')" /></form>