意外警报被调用
[英]Unexpected alert being called
问题描述
I have the following simple script on a page
我在页面上有以下简单脚本
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Untitled Page</title>
<script type="text/javascript">
var nsTest = function ()
{
var test = function ()
{
alert('nsTest.test');
}
var test2 = function ()
{
alert('nsTest.test2');
}
return {
test: test,
test2: test2
}
} ();
function t()
{
alert(nsTest.test());
}
function t2()
{
alert(nsTest.test2());
}
</script>
</head>
<body>
<input type="button" value="test" onclick="t()" />
<input type="button" value="test2" onclick="t2()" />
</body>
</html>
When I click on either of the buttons I see the expected alert on the screent and then a second alert that says 'undefined'.当我单击任一按钮时，我会在屏幕上看到预期的警报，然后是第二个警报，显示“未定义”。
This is happening in IE8 and FF3.这发生在 IE8 和 FF3 中。 Any ideas what is going on?有什么想法吗？
Thanks,谢谢，
David大卫
3 个解决方案
解决方案1
3 已采纳 2011-05-03 10:51:45
Your saying alert twice.你这句话提醒了两次。 You do not need to say你不需要说
alert(nsTest.test2());警报（nsTest.test2（））；
you just need to call nsTest.test2();你只需要调用 nsTest.test2();
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Untitled Page</title>
<script type="text/javascript">
var nsTest = function ()
{
var test = function ()
{
alert('nsTest.test');
}
var test2 = function ()
{
alert('nsTest.test2');
}
return {
test: test,
test2: test2
}
}();
function t()
{
nsTest.test();
}
function t2()
{
nsTest.test2();
}
</script>
</head>
<body>
<input type="button" value="test" onclick="t()" />
<input type="button" value="test2" onclick="t2()" />
</body>
</html>
Actually you do not even need a function t1 and t2 you can just have your onclick reference nsTest.test2() directly as shown here http://jsbin.com/ageva5/2/edit实际上你甚至不需要 function t1 和 t2 你可以直接让你的 onclick 参考 nsTest.test2() 如下所示Z80791B3AE7002CB88C246876D9FAAbin.com/age
解决方案2
1 2011-05-03 10:51:46
You call t() which calls nsTest.test() …你调用t()调用nsTest.test() ...
nsTest.test() alerts the string 'nsTest.test' and then has no return value so returns undefined . nsTest.test()警告字符串'nsTest.test'然后没有返回值，因此返回undefined 。
… t() then receives the return value and alerts it. … t()然后接收返回值并警告它。
解决方案3
1 2011-05-03 10:51:52
First the alerts in nsTest are run then the alerts in t() and t2() are run.首先运行 nsTest 中的警报，然后运行 t() 和 t2() 中的警报。 These alerts alert the return value of nsTest.*.这些警报提醒 nsTest.* 的返回值。 These value are undefined.这些值是未定义的。 Remove these alerts to only get the first alert.删除这些警报以仅获取第一个警报。
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