如何在 JavaScript 中获取 <a> 标签的值
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How to get value of <a> tag in JavaScript
提问by TIto Amoo
I have this code:
我有这个代码：
<html>
<BUTTON ONCLICK="stups()">VALUE FINDER </BUTTON>
<a value="this is a value" href="value"><img src="b5.jpg"> values rule!!</a>
<p id="demo"></p>
<script>
var a = document.getElementsByTagName("a").value
function stups(){
document.getElementById("demo").innerHTML=a
}
</script>
</html>
The javascript is simply meant to get the value of th (link) when the button is clicked I don't even know what is supposed to be the value whether it is th hrefattribute, the valueattribute ,the value of the imgattribute or the text in between the two <a>and </a>,well I've tried EVERYTHING i could think of and it never gives me any value it keeps giving me the word undefined.Please help.
javascript 只是为了在单击按钮时获取 th（链接）的值我什至不知道应该是什么值，无论是 thhref属性、value属性、属性值img还是中的文本两者之间<a>和</a>，以及我已经试过所有我能想到的，它从来没有给我，它不断给我的字的任意值 undefined。请帮助。
NB:I needthat to be in between the
<a></a>because it is a link
注意：我需要它介于两者之间，
<a></a>因为它是一个链接
Thanks in advance
提前致谢
回答by BraveButter
You need to define which attribute you need from the atag.
您需要从a标签中定义您需要的属性。
So try .getAttribute('value')
所以试试 .getAttribute('value')
<html>
<button onclick="stups()">VALUE FINDER </button>
<a value="this is a value" href="value"><img src="b5.jpg"> values rule!!</a>
<p id="demo"></p>
<script>
function stups(){
var a = document.getElementsByTagName('a')[0].getAttribute('value');
document.getElementById("demo").innerHTML=a
}
</script>
</html>回答by Takit Isy
First of all, take care of what you want to do, because .getElementsByTagName("a")will return you a collection of elements.
首先，照顾好你想要做什么，因为它.getElementsByTagName("a")会返回一个元素集合。
Then, you might want to use .getAttribute("value"):
然后，您可能想要使用.getAttribute("value")：
var a = document.getElementsByTagName("a");
function stups(){
document.getElementById("demo").innerHTML = a[0].getAttribute("value");
}<BUTTON ONCLICK="stups()">VALUE FINDER </BUTTON>
<a value="this is a value" href="value"><img src="b5.jpg"> values rule!!</a>
<p id="demo"></p>? ? ?
? ? ?
If you want to manage multiple aelements, you could do the following:
如果要管理多个a元素，可以执行以下操作：
- Use a
.querySelectorAll("a"), to be able to use aforEachloop directly, .push()your values in an array,- Do what you want with your array.
- 使用 a
.querySelectorAll("a"), 可以forEach直接使用循环， .push()您在数组中的值，- 用你的阵列做你想做的事。
var as = document.querySelectorAll("a");
function stups(){
var values = [];
as.forEach(function(a, index){
values.push(a.getAttribute("value") || '--- no value ---');
// OR: values.push(as[index].getAttribute("value"));
})
document.getElementById("demo").innerHTML = values.join('<br>');
}<BUTTON ONCLICK="stups()">VALUE FINDER </BUTTON>
<a value="this is a value" href="value"><img src="b5.jpg"> values rule!!</a>
<a value="this is another value" href="value"><img src="b5.jpg"> values rule!!</a>
<a href="value"><img src="b5.jpg">No value here</a>
<a value="this is another value, again" href="value"><img src="b5.jpg"> values rule!!</a>
<p id="demo"></p>Hope it helps.
希望能帮助到你。
回答by Aplet123
In these situations, MDN is your friend.You also shouldn't be copy-pasting code you don't understand. The srcof the imgpoints to whatever image is being displayed. The hrefof the atag is the actual link. The text inside the a tag is what shows up. You should not be setting the valueattribute of the atag as it is non-standard and not needed. document.getElementsByTagName("a")returns an array of every atag in the document. You need to specify the first link by running document.getElementsByTagName("a")[0]. You can get the link just by using .href. In the end, the stupsfunction should look something like this:
在这些情况下，MDN 是您的朋友。您也不应该复制粘贴您不理解的代码。在src对的img点，正在显示任何图像。在href该的a标签是实际的链接。a 标签内的文本是显示的内容。您不应该设置标签的value属性，a因为它是非标准的且不需要。document.getElementsByTagName("a")返回a文档中每个标签的数组。您需要通过运行指定第一个链接document.getElementsByTagName("a")[0]。您只需使用 即可获取链接.href。最后，该stups函数应如下所示：
function stups(){
var a = document.getElementsByTagName("a")[0].href;
document.getElementById("demo").innerHTML = a;
}
