如何使用JavaScript更改HTML标签

Question

I have some HTML code that looks like this:

<textarea name="message"></textarea>

And I would like to change it to this:

<textarea maxlength="300" name="message"></textarea>

How can I accomplish this using Javascript? I have tried a lot of different code from a lot of different places, but none of them seem to work. If need be, I will accept CSS code too.

Answer 1

Here's how you do it if you aren't using jQuery (highly recommended):

var myelement = document.getElementsByName('message')[0];
myelement.setAttribute('maxlength',300);

Here's the jsFiddle

Answer 2

使用jquery匹配tag元素，然后使用.attr（）函数。

Answer 3

Since you're not using jQuery:

<textarea id="text" name="message"></textarea>

var element = document.getElementById("text");
element.setAttribute("maxlength","300");

Example

Answer 4

document.querySelector('[name="message"]').setAttribute('maxlength', 300)

Answer 5

$('textarea').attr('maxlength', 300);