問題描述
我最近開始學習 JavaScript，但有些東西讓我感到困惑:
I've started learning JavaScript recently but there's something that I'm confused with :
Element.value 和 Element.getAttribute("value")
實際上我的問題是，當我嘗試將類型為 text 的 input 元素的值復制到另一個時，如果我使用第一種方法(Element.value) 它工作正常，但是如果我使用第二種方法它會復制給元素的第一個值，并且當我更改 textbox 內的文本時它永遠不會更新，這種行為對我來說似乎很奇怪！你們能解釋一下這里發生了什么嗎?
actually my problem is , when I try to copy the value of an input element with type of text to another one , if I use the first method (Element.value) It works fine but if I go with the second method It copies the first value given to the element and It never gets updated when I change the text inside the textbox , this behavior seems odd to me ! can you guys please explain what's going on here ?
<html>
<head>
<meta charset="utf-8">
<title>Hello JavaScript</title>
<script src="script2.js"></script>
</head>
<body>
<input id="Text1" type="text" />
<input id="Button1" type="button" value="button" />
<input id="Text2" type="text" />
</body>
</html>
JavaScript 文件:
The JavaScript file :
var myButton;
window.onload = function () {
myButton = document.getElementById("Button1");
myButton.onclick = function () {
var val = document.getElementById("Text1").getAttribute("value");
//var val = document.getElementById("Text1").value;
document.getElementById("Text2").setAttribute("value", val);
};
};
推薦答案
不同之處在于 element.value 是實時的，如果用戶更改，比如說文本框輸入，它將反映，并向您展示新值.
The difference is that element.value is real time and if a user changes let's say, a textbox input, it will reflect that, and show you the new value.
雖然 getAttribute('value') 仍會顯示原始 value="whateverWasHere" 值.
While getAttribute('value') will still show the original value="whateverWasHere" value.
jsFiddle 演示
這篇關于JavaScript Element.value 與 Element.getAttribute("value")的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！