javascript - ClipboardData - 未捕获类型错误 : Cannot read property 'length' of undefined

Question

这是抛出错误的代码，不知道为什么，它曾经与 Chrome 一起使用。我现在使用 Chromium，它抛出错误 Uncaught TypeError: Cannot read property 'length' of undefined

$wnd.addEventListener("paste",processEvent);
        function processEvent(e) {
    if (e.clipboardData && e.clipboardData.getData) {
        console.log("clipboard from event"); // can see in console log
        var items = e.clipboardData.items;
        if(items.length == 0){ // error here

        }
    }
}

看来问题是 var items 未定义

Answer 1

我会检查items是否首先被定义

$wnd.addEventListener("paste",processEvent);

    function processEvent(e) {

if (e.clipboardData && e.clipboardData.getData) {

    console.log("clipboard from event"); // can see in console log
    var items = e.clipboardData.items;
    if(items != undefined && items.length == 0){ // error here

    }
}
}

但是你cannot read or set clip board data in JavaScript