Javascript 未捕获的类型错误：无法读取 null 的属性“children”
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Uncaught TypeError: Cannot read property 'children' of null
提问by Remento
I am very new to Javascript. I am having an error:
我对 Javascript 很陌生。我有一个错误：
Uncaught TypeError: Cannot read property 'children' of null fiddle.jshell.net:1163 (anonymous function)
未捕获的类型错误：无法读取 null fiddle.jshell.net:1163 的属性“children”（匿名函数）
How to fix the error?
如何修复错误？
Providing my fiddle below:
在下面提供我的小提琴：
http://jsfiddle.net/N3GTy/29/embedded/result/
http://jsfiddle.net/N3GTy/29/embedded/result/
var slider = new Swipe(document.getElementById('slider'), {
callback: function(e, pos) {
var i = bullets.length;
while (i--) {
bullets[i].className = ' ';
}
bullets[pos].className = 'on';
}
}),
bullets = document.getElementById('position').getElementsByTagName('em'),
// tabs
tabs = new Swipe(document.getElementById('tabs'), {
callback: function(event, index, elem) {
setTab(selectors[index]);
}
}),
selectors = document.getElementById('tabSelector').children;
Uncaught TypeError: Cannot read property 'children' of null
for (var i = 0; i < selectors.length; i++) {
var elem = selectors[i];
elem.setAttribute('data-tab', i);
elem.onclick = function(e) {
e.preventDefault();
setTab(this);
tabs.slide(parseInt(this.getAttribute('data-tab'), 10), 300);
}
}
回答by Remento
There is no element with an id of "tabSelector". So, document.getElementById('tabSelector') returns null. I tested this with chrome's debugger by going to:
没有 ID 为“tabSelector”的元素。因此， document.getElementById('tabSelector') 返回 null。我通过以下方式使用 chrome 的调试器对此进行了测试：
http://fiddle.jshell.net/N3GTy/29/show/light/
http://fiddle.jshell.net/N3GTy/29/show/light/
and running two commands from the chrome debugger console:
并从 chrome 调试器控制台运行两个命令：
document.getElementById('slider'); Returns a domNode as you would expect.
document.getElementById('slider'); 如您所料，返回一个 domNode。
document.getElementById('tabSelector'); Returns null, because it does not exist.
document.getElementById('tabSelector'); 返回 null，因为它不存在。
calling null.children then results in your error.
调用 null.children 然后导致你的错误。
