這已被問到100x之前,但閱讀了很多這些帖子後,我仍然不知道我做錯了什麼。該腳本僅在按下按鈕時執行(因此,在執行代碼時文本框應該存在於DOM中),Visual Studio甚至允許我自動完成inputField的getElementByID參數。然而不知何故,它沒有得到元素,'null'被打印在我的屏幕上。Js:GetElementByID()不返回我的元素
我的代碼是:
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
<!-- input field + button, and an empty value field -->
<input type="text" id="inputField" value="" />
<input type="button" onclick="printType()" />
</body>
<script>
function printType() {
console.log(document.getElementById(inputField).value); //first try to get the value the regular way
console.log(
get_type(
document.getElementById(inputField)
)
); //also try get_type to see if it exists, we're expecting a string
}
//stole this function from a stackoverflow post
function get_type(thing) {
if (thing === null) return "[object Null]"; // special case
return Object.prototype.toString.call(thing);
}
</script>
</html>
你可以在瀏覽器中進行控制嗎? – binariedMe
[爲什麼jQuery或諸如getElementById之類的DOM方法未找到該元素?](http://stackoverflow.com/questions/14028959/why-does-jquery-or-a-dom-method-such- as-getelementbyid-not-the-element) – Teemu
Visual Studio是否抱怨未聲明的變量? – Teemu