632
votes

It seems the minlength attribute for an <input> field doesn't work.

Is there any other attribute in HTML5 with the help of which I can set the minimal length of a value for fields?

19
It won't be the answer for every field, but if you just want to make sure a value is there you can use the "required" attribute. <input type="text" name="input1" required="required" />None
It doesn't exist, but let's make a fuss and get it in! w3.org/Bugs/Public/show_bug.cgi?id=20557Eric Elliott
You need to use JS/Jquery if you want to do a full implementation (eg. required, minlength, error message when submitting etc). Safari still does not fully support even the required attribute, and only Chrome and Opera support minLength. eg see caniuse.com/#search=requiredrmcsharry

19 Answers

1375
votes

You can use the pattern attribute. The required attribute is also needed, otherwise an input field with an empty value will be excluded from constraint validation.

<input pattern=".{3,}"   required title="3 characters minimum">
<input pattern=".{5,10}" required title="5 to 10 characters">

If you want to create the option to use the pattern for "empty, or minimum length", you could do the following:

<input pattern=".{0}|.{5,10}" required title="Either 0 OR (5 to 10 chars)">
<input pattern=".{0}|.{8,}"   required title="Either 0 OR (8 chars minimum)">
165
votes

There is a minlength property in the HTML5 specification now, as well as the validity.tooShort interface.

Both are now enabled in recent versions of all modern browsers. For details, see https://caniuse.com/#search=minlength.

19
votes

Here is HTML5-only solution (if you want minlength 5, maxlength 10 character validation)

http://jsfiddle.net/xhqsB/102/

<form>
  <input pattern=".{5,10}">
  <input type="submit" value="Check"></input>
</form>
12
votes

Yes, there it is. It's like maxlength. W3.org documentation: http://www.w3.org/TR/html5/forms.html#attr-fe-minlength

In case minlength doesn't work, use the pattern attribute as mentioned by @Pumbaa80 for the input tag.

For textarea: For setting max; use maxlength and for min go to this link.

You will find here both for max and min.

8
votes

I used maxlength and minlength with or without required and it worked for me very well for HTML5.

<input id="passcode" type="password" minlength="8" maxlength="10">

`

5
votes

minlength attribute is now widely supported in most of the browsers.

<input type="text" minlength="2" required>

But, as with other HTML5 features, IE11 is missing from this panorama. So, if you have a wide IE11 user base, consider using the pattern HTML5 attribute that is supported almost across the board in most browsers (including IE11).

To have a nice and uniform implementation and maybe extensible or dynamic (based on the framework that generate your HTML), I would vote for the pattern attribute:

<input type="text" pattern=".{2,}" required>

There is still a small usability catch when using pattern. The user will see a non-intuitive (very generic) error/warning message when using pattern. See this jsfiddle or below:

<h3>In each form type 1 character and press submit</h3>
</h2>
<form action="#">
  Input with minlength: <input type="text" minlength="2" required name="i1">
  <input type="submit" value="Submit">
</form>
<br>
<form action="#">
  Input with patern: <input type="text" pattern=".{2,}" required name="i1">
  <input type="submit" value="Submit">
</form>

For example, in Chrome (but similar in most browsers), you will get the following error messages:

Please lengthen this text to 2 characters or more (you are currently using 1 character)

by using minlength and

Please match the format requested

by using pattern.

5
votes

I notice that sometimes in Chrome when autofill is on and the fields are field by the autofill browser build in method, it bypasses the minlength validation rules, so in this case you will have to disable autofill by the following attribute:

autocomplete="off"

<input autocomplete="new-password" name="password" id="password" type="password" placeholder="Password" maxlength="12" minlength="6" required />
5
votes

The minLength attribute (unlike maxLength) does not exist natively in HTML5. However, there a some ways to validate a field if it contains less than x characters.

An example is given using jQuery at this link: http://docs.jquery.com/Plugins/Validation/Methods/minlength

<html>
    <head>
        <script src="http://code.jquery.com/jquery-latest.js"></script>
        <script type="text/javascript" src="http://jzaefferer.github.com/jquery-validation/jquery.validate.js"></script>
        <script type="text/javascript">
            jQuery.validator.setDefaults({
                debug: true,
                success: "valid"
            });;
        </script>

        <script>
            $(document).ready(function(){
                $("#myform").validate({
                    rules: {
                        field: {
                            required: true,
                            minlength: 3
                        }
                    }
                });
            });
        </script>
    </head>

    <body>
        <form id="myform">
            <label for="field">Required, Minimum length 3: </label>
            <input class="left" id="field" name="field" />
            <br/>
            <input type="submit" value="Validate!" />
        </form>
    </body>

</html>
5
votes

Not HTML5, but practical anyway: if you happen to use AngularJS, you can use ng-minlength (or data-ng-minlength) for both inputs and textareas. See also this Plunk.

4
votes

My solution for textarea using jQuery and combining HTML5 required validation to check the minimum length.

minlength.js

$(document).ready(function(){
  $('form textarea[minlength]').on('keyup', function(){
    e_len = $(this).val().trim().length
    e_min_len = Number($(this).attr('minlength'))
    message = e_min_len <= e_len ? '' : e_min_len + ' characters minimum'
    this.setCustomValidity(message)
  })
})

HTML

<form action="">
  <textarea name="test_min_length" id="" cols="30" rows="10" minlength="10"></textarea>
</form>
4
votes

See http://caniuse.com/#search=minlength. Some browsers may not support this attribute.


If the value of the "type" is one of them:

text, email, search, password, tel, or URL (warning: not include number | no browser support "tel" now - 2017.10)

Use the minlength(/ maxlength) attribute. It specifies the minimum number of characters.

For example,

<input type="text" minlength="11" maxlength="11" pattern="[0-9]*" placeholder="input your phone number">

Or use the "pattern" attribute:

<input type="text" pattern="[0-9]{11}" placeholder="input your phone number">

If the "type" is number, although minlength(/ maxlength) is not be supported, you can use the min(/ max) attribute instead of it.

For example,

<input type="number" min="100" max="999" placeholder="input a three-digit number">
2
votes

New version:

It extends the use (textarea and input) and fixes bugs.

// Author: Carlos Machado
// Version: 0.2
// Year: 2015
window.onload = function() {
    function testFunction(evt) {
        var items = this.elements;
        for (var j = 0; j < items.length; j++) {
            if ((items[j].tagName == "INPUT" || items[j].tagName == "TEXTAREA") && items[j].hasAttribute("minlength")) {
                if (items[j].value.length < items[j].getAttribute("minlength") && items[j].value != "") {
                    items[j].setCustomValidity("The minimum number of characters is " + items[j].getAttribute("minlength") + ".");
                    items[j].focus();
                    evt.defaultPrevented;
                    return;
                }
                else {
                    items[j].setCustomValidity('');
                }
            }
        }
    }
    var isOpera = !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
    var isChrome = !!window.chrome && !isOpera;
    if(!isChrome) {
        var forms = document.getElementsByTagName("form");
        for(var i = 0; i < forms.length; i++) {
            forms[i].addEventListener('submit', testFunction,true);
            forms[i].addEventListener('change', testFunction,true);
        }
    }
}
1
votes

I wrote this JavaScript code, [minlength.js]:

window.onload = function() {
    function testaFunction(evt) {
        var elementos = this.elements;
        for (var j = 0; j < elementos.length; j++) {
            if (elementos[j].tagName == "TEXTAREA" && elementos[j].hasAttribute("minlength")) {
                if (elementos[j].value.length < elementos[j].getAttribute("minlength")) {
                    alert("The textarea control must be at least " + elementos[j].getAttribute("minlength") + " characters.");
                    evt.preventDefault();
                };
            }
        }
    }
    var forms = document.getElementsByTagName("form");
    for(var i = 0; i < forms.length; i++) {
        forms[i].addEventListener('submit', testaFunction, true);
    }
}
1
votes

In my case, in which I validate the most manually and using Firefox (43.0.4), minlength and validity.tooShort are not available unfortunately.

Since I only need to have minimum lengths stored to proceed, an easy and handy way is to assign this value to another valid attribute of the input tag. In that case then, you can use min, max, and step properties from [type="number"] inputs.

Rather than storing those limits in an array it's easier to find it stored in the same input instead of getting the element id to match the array index.

1
votes

I used max and min then required, and it worked for me very well, but what am not sure is if it is a but coding method.

<input type="text" maxlength="13" name ="idnumber" class="form-control"  minlength="13" required>
1
votes

If desired to make this behavior, always show a small prefix on the input field or the user can't erase a prefix:

   // prefix="prefix_text"
   // If the user changes the prefix, restore the input with the prefix:
   if(document.getElementById('myInput').value.substring(0,prefix.length).localeCompare(prefix))
       document.getElementById('myInput').value = prefix;
1
votes

Following @user123444555621 pinned answer.

There is a minlength attribute in HTML5 but for some reason it may not always work as expected.

I had a case where my input type text did not obey the minlength="3" property.

By using the pattern attribute I managed to fix my problem. Here's an example of using pattern to ensure minlength validation:

const folderNameInput = document.getElementById("folderName");

folderNameInput.addEventListener('focus', setFolderNameValidityMessage);
folderNameInput.addEventListener('input', setFolderNameValidityMessage);

function setFolderNameValidityMessage() {
  if (folderNameInput.validity.patternMismatch || folderNameInput.validity.valueMissing) {
      folderNameInput.setCustomValidity('The folder name must contain between 3 and 50 chars');
  } else {
      folderNameInput.setCustomValidity('');
  }
}
:root {
  --color-main-red: rgb(230, 0, 0);
  --color-main-green: rgb(95, 255, 143);
}

form input {
  border: 1px solid black;
  outline: none;
}

form input:invalid:focus {
  border-bottom-color: var(--color-main-red);
  box-shadow: 0 2px 0 0 var(--color-main-red);
}

form input:not(:invalid):focus {
  border-bottom-color: var(--color-main-green);
  box-shadow: 0 2px 0 0 var(--color-main-green);
}
<form>
  <input
    type="text"
    id="folderName"
    placeholder="Your folder name"
    spellcheck="false"
    autocomplete="off"
    
    required
    minlength="3"
    maxlength="50"
    pattern=".{3,50}"
  />
  <button type="submit" value="Create folder">Create folder</button>
</form>

For further details, here's the MDN link to the HTML pattern attribute: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/pattern

0
votes

You can use minlength in input tag or you can regex pattern to check the number of character or even you can take the input and check the length of the character and then you can restrict based upon your requirement.

-4
votes

Add both a maximum and a minimum value. You can specify the range of allowed values:

<input type="number" min="1" max="999" />