Question

当我在浏览器中执行以下代码时：

for (propt in location) {
   document.write("location property " + propt + " is currently: ");
   document.write(screen[propt] + "<br />\n");
}

所有属性都未定义。为什么会这样？

这是输出：

location property assign is currently: undefined
location property replace is currently: undefined
location property reload is currently: undefined
location property ancestorOrigins is currently: undefined
location property origin is currently: undefined
location property hash is currently: undefined
location property search is currently: undefined
location property pathname is currently: undefined
location property port is currently: undefined
location property hostname is currently: undefined
location property host is currently: undefined
location property protocol is currently: undefined
location property href is currently: undefined

Answer 1

如上所述here，您需要使用条件语句包装for in循环体。这是因为位置属性包括通过以下方式执行的功能：分配，替换，重新加载等。

此外，当您需要使用screen[propt]时，您正在使用location[propt]。

以下是正确的代码：

for (propt in location) {
    if (location.hasOwnProperty(propt) && typeof location[propt] !== 'function'){
        document.write("location property " + propt + " is currently: ");
        document.write(location[propt] + "<br />\n");
    }
}

Answer 2

嗯......您正在循环浏览location，但访问screen上的属性。这个代码是你复制粘贴的吗？

document.write(location[propt] +"<br />\n");

Answer 3

for (propt in location) {
   document.write("location property " + propt + " is currently: ");
   document.write(propt + "<br />\n");
}

似乎有用

Javascript位置属性未定义

3 个答案: