我如何退出JavaScript脚本,就像PHP的退出或死亡?我知道这不是最好的编程实践,但我需要这样做。
当前回答
这个小函数非常接近于模仿PHP的exit()。与其他解决方案一样,不要添加任何其他解决方案。
function exit(Msg)
{
Msg=Msg?'*** '+Msg:'';
if (Msg) alert(Msg);
throw new Error();
} // exit
其他回答
JavaScript相当于PHP的die。顺便说一句,它只是调用exit()(谢谢splattne):
function exit( status ) {
// http://kevin.vanzonneveld.net
// + original by: Brett Zamir (http://brettz9.blogspot.com)
// + input by: Paul
// + bugfixed by: Hyam Singer (http://www.impact-computing.com/)
// + improved by: Philip Peterson
// + bugfixed by: Brett Zamir (http://brettz9.blogspot.com)
// % note 1: Should be considered expirimental. Please comment on this function.
// * example 1: exit();
// * returns 1: null
var i;
if (typeof status === 'string') {
alert(status);
}
window.addEventListener('error', function (e) {e.preventDefault();e.stopPropagation();}, false);
var handlers = [
'copy', 'cut', 'paste',
'beforeunload', 'blur', 'change', 'click', 'contextmenu', 'dblclick', 'focus', 'keydown', 'keypress', 'keyup', 'mousedown', 'mousemove', 'mouseout', 'mouseover', 'mouseup', 'resize', 'scroll',
'DOMNodeInserted', 'DOMNodeRemoved', 'DOMNodeRemovedFromDocument', 'DOMNodeInsertedIntoDocument', 'DOMAttrModified', 'DOMCharacterDataModified', 'DOMElementNameChanged', 'DOMAttributeNameChanged', 'DOMActivate', 'DOMFocusIn', 'DOMFocusOut', 'online', 'offline', 'textInput',
'abort', 'close', 'dragdrop', 'load', 'paint', 'reset', 'select', 'submit', 'unload'
];
function stopPropagation (e) {
e.stopPropagation();
// e.preventDefault(); // Stop for the form controls, etc., too?
}
for (i=0; i < handlers.length; i++) {
window.addEventListener(handlers[i], function (e) {stopPropagation(e);}, true);
}
if (window.stop) {
window.stop();
}
throw '';
}
If you're looking for a way to forcibly terminate execution of all Javascript on a page, I'm not sure there is an officially sanctioned way to do that - it seems like the kind of thing that might be a security risk (although to be honest, I can't think of how it would be off the top of my head). Normally in Javascript when you want your code to stop running, you just return from whatever function is executing. (The return statement is optional if it's the last thing in the function and the function shouldn't return a value) If there's some reason returning isn't good enough for you, you should probably edit more detail into the question as to why you think you need it and perhaps someone can offer an alternate solution.
注意,在实践中,大多数浏览器的Javascript解释器在遇到错误时会简单地停止运行当前脚本。所以你可以做一些事情,比如访问一个未设置变量的属性:
function exit() {
p.blah();
}
它可能会中止脚本。但你不应该指望它,因为它根本不是标准的,而且它看起来真的是一个糟糕的做法。
编辑:好吧,也许这不是一个很好的答案Ólafur的光。尽管他链接到的die()函数基本上实现了我的第二段,即它只是抛出一个错误。
要停止脚本执行而不出现任何错误,可以将所有脚本包含到函数中并执行它。 这里有一个例子: (函数(){ console.log(一); 返回; console.log(两个); }) ();
上面的脚本将只记录一个日志。
在使用前
如果您需要在脚本本身之外读取脚本的函数,请记住(通常)这是行不通的:要做到这一点,您需要使用一个预先存在的变量或对象(您可以将函数放在窗口对象中)。 上面的代码可能是你不想要的:将整个脚本放在一个函数中可能会产生其他后果(例如,这样做,脚本将立即运行,并且没有办法从浏览器开发中修改其部分,正如我所知道的,在Chrome中)
我知道这是旧的,但如果你想要一个类似的PHP die()函数,你可以这样做:
function die(reason) {
throw new Error(reason);
}
用法:
console.log("Hello");
die("Exiting script..."); // Kills script right here
console.log("World!");
上面的例子只打印“Hello”。
即使在没有句柄、事件等的简单程序中,最好将代码放在主函数中,即使它是唯一的过程:
<script>
function main()
{
//code
}
main();
</script>
这样,当你想要停止程序时,你可以使用return。