Character Limit in HTML

问题:

How do you impose a character limit on a text input in HTML?

回答1:

There are 2 main solutions:

The pure HTML one:

<input type="text" id="Textbox" name="Textbox" maxlength="10" />

The JavaScript one (attach it to a onKey Event):

function limitText(limitField, limitNum) {
    if (limitField.value.length > limitNum) {
        limitField.value = limitField.value.substring(0, limitNum);
    } 
}

But anyway, there is no good solution. You can not adapt to every client's bad HTML implementation, it's an impossible fight to win. That's why it's far better to check it on the server side, with a PHP / Python / whatever script.

回答2:

there's a maxlength attribute

<input type="text" name="textboxname" maxlength="100" />

回答3:

In addition to the above, I would like to point out that client-side validation (HTML code, javascript, etc.) is never enough. Also check the length server-side, or just don't check at all (if it's not so important that people can be allowed to get around it, then it's not important enough to really warrant any steps to prevent that, either).

Also, fellows, he (or she) said HTML, not XHTML. ;)

回答4:

use the "maxlength" attribute as others have said.

if you need to put a max character length on a text AREA, you need to turn to Javascript. Take a look here: How to impose maxlength on textArea in HTML using JavaScript

回答5:

For the <input> element there's the maxlength attribute:

<input type="text" id="Textbox" name="Textbox" maxlength="10" />

(by the way, the type is "text", not "textbox" as others are writing), however, you have to use javascript with <textarea>s. Either way the length should be checked on the server anyway.

回答6:

you can set maxlength with jquery which is very fast

jQuery(document).ready(function($){ //fire on DOM ready
 setformfieldsize(jQuery('#comment'), 50, 'charsremain')
})