检查表单数据是否改变
检查表单数据是否改变下面介绍一种检查表单数据是否改变的方法，如果修改了表单的内容则返回true，没修改则返回false
function formIsDirty(form) {
for (var i = 0; i < form.elements.length; i++) {
var element = form.elements[i];
var type = element.type;
if (type == "checkbox" || type == "radio") {
if (element.checked != element.defaultChecked) {
return true;
}
}
else if (type == "hidden" || type == "password" ||
type == "text" || type == "textarea") {
if (element.value != element.defaultValue) {
return true;
}
}
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) {
return true;
}
}
}
}
return false;
}
window.onbeforeunload = function(e) {
e = e || window.event;
if (formIsDirty(document.forms["someForm"])) {
// IE 和 Firefox
if (e) {
e.returnValue = "You have unsaved changes.";
}
// Safari 浏览器
return "You have unsaved changes.";
}
};
