javascript 未捕获的类型错误：无法读取未定义的属性“关闭”
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Uncaught TypeError: Cannot read property 'close' of undefined
提问by mahesh
When i compile the following code , it works fine , but in console i get error: Uncaught TypeError: Cannot read property 'close' of undefined
当我编译以下代码时，它工作正常，但在控制台中我收到错误：Uncaught TypeError: Cannot read property 'close' of undefined
<!DOCTYPE html>
<html>
<body>
<button onclick="openWin()">Open "myWindow"</button>
<button onclick="closeWin()">Close "myWindow"</button>
<script>
var myWindow;
function openWin(){
myWindow = window.open("http://www.w3schools.com", "myWindow");
}
function closeWin() {
myWindow.close();
}
</script>
</body>
</html>var myWindow;
function openWin(){
myWindow = window.open("http://www.w3schools.com/", "myWindow");
}
function closeWin() {
myWindow.close();
}i tried to call the above js file externally also, i get the same error
我也尝试在外部调用上述 js 文件，但出现相同的错误
回答by slomek
You have to click Open "myWindow"button before clicking the other one, because that is when the variable myWindow gets initial value.
您必须Open "myWindow"在单击另一个按钮之前单击按钮，因为那是变量 myWindow 获得初始值的时候。
You should check if window has been opened before trying to close it:
在尝试关闭窗口之前，您应该检查窗口是否已打开：
function closeWin() {
if(myWindow){
myWindow.close();
}
}
If myWindowis not set, you just do nothing (as there is nothing to be closed, right?).
如果myWindow没有设置，你什么都不做（因为没有什么可以关闭的，对吧？）。
