<form> <input type="text" value="defaultValue 1"/> <input type="text" value="defaultValue 2"/> <textarea >defaultValue 1</textarea> <textarea >defaultValue 2</textarea> <input type="radio" name="a" />test <input type="radio" name="a" checked="checked"/>defaultChecked <input type="checkbox" name="b"/>test <input type="checkbox" name="b" checked="checked"/>defaultChecked <input type="checkbox" name="b" checked="checked"/>defaultChecked <select> <option selected="selected">defaultSelected 1</option> <option>test</option> <option>test</option> <option>test</option> </select> <select multiple="multiple"> <option>test</option> <option selected="selected">defaultSelected 1</option> <option selected="selected">defaultSelected 2</option> <option>test</option> </select> <input type="button" onclick="IsFormChanged()" value="submit"/> </form> <script> function IsFormChanged() { var isChanged = false; var form = document.forms[0]; for (var i = 0; i < form.elements.length; i++) { var element = form.elements[i]; var type = element.type; if (type == "text" || type == "hidden" || type == "textarea" || type == "button") { if (element.value != element.defaultValue) { isChanged = true; break; } } else if (type == "radio" || type == "checkbox") { if (element.checked != element.defaultChecked) { isChanged = true; break; } } else if (type == "select-one"|| type == "select-multiple") { for (var j = 0; j < element.options.length; j++) { if (element.options[j].selected != element.options[j].defaultSelected) { isChanged = true; break; } } } else { // etc... } } alert( isChanged?"你改变了表单的默认值.":"成功提交."); return isChanged; } </script>
有2点注意1，表单元素都有默认值属性，比如element.defaultValue ， element.defaultChecked ，element.options[j].defaultSelected2，select元素的type类型是：""select-one"或者"select-multiple"，而不是"select"。
