Use CSS to automatically add 'required field&#

Question

What is a good way to overcome the unfortunate fact that this code will not work as desired:

<div class="required">
    <label>Name:</label>
    <input type="text">
</div>

<style>
    .required input:after { content:"*"; }
</style>

In a perfect world, all required inputs would get the little asterisk indicating that the field is required. This solution impossible since the CSS is inserted after the element content, not after the element itself, but something like it would be ideal. On a site with thousands of required fields, I can move the asterisk in front of the input with one change to one line (:after to :before) or I can move it to the end of the label (.required label:after) or in front of the label, or to a position on the containing box, etc...

This is important not just in case I change my mind about where to place the asterisk everywhere, but also for odd cases where the form layout doesn't allow the asterisk in the standard position. It also plays well with validation that checks the form or highlights improperly completed controls.

Lastly, it doesn't add additional markup.

Are there any good solutions that have all or most of the advantages of the impossible code?

Answer 1

It is 2019 and previous answers to this problem are not using

1. CSS grid
2. CSS variables
3. HTML5 form elements
4. SVG in CSS

CSS grid is the way to do forms in 2019 as you can have your labels preceding your inputs without having extra divs, spans, spans with asterisks in and other relics.

Here is where we are going with minimal CSS:

The HTML for the above:

<form action="https://www.example.com/register/" method="post" id="form-validate" enctype="multipart/form-data">
    <p class="form-instructions">Please enter the following information to create your account.</p>
    <label for="firstname">First name</label>
    <input type="text" id="firstname" name="firstname" value="" title="First name" maxlength="255" required="">
    <label for="lastname">Last name</label>
    <input type="text" id="lastname" name="lastname" value="" title="Last name" maxlength="255" required="">
    <label for="email_address">Email address</label>
    <input type="email" autocapitalize="off" autocorrect="off" spellcheck="false" name="email" id="email_address" value="" title="Email address" size="30" required="">
    <label for="password">Password</label>
    <input type="password" name="password" id="password" title="Password" required="">
    <label for="confirmation">Confirm password</label>
    <input type="password" name="confirmation" title="Confirm password" id="confirmation" required="">
    <input type="checkbox" name="is_subscribed" title="Subscribe to our newsletter" value="1" id="is_subscribed" class="checkbox">
    <label for="is_subscribed">Subscribe to the newsletter</label>
    <input type="checkbox" name="persistent_remember_me" id="remember_meGCJiRe0GbJ" checked="checked" title="Remember me">
    <label for="remember_meGCJiRe0GbJ">Remember me</label>
    <p class="required">* Required</p>
    <button type="submit" title="Register">Register</button>
</form>

Placeholder text can be added too and is highly recommended. (I am just answering this mid-form).

Now for the CSS variables:

--icon-required: url('data:image/svg+xml,\
<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="-10 -6 16 16"> \
  <line id="line" y1="-3" y2="3" stroke="%23df0000" stroke-linecap="butt" transform="rotate(15)"></line> \
  <line id="line" y1="-3" y2="3" stroke="%23df0000" stroke-linecap="butt" transform="rotate(75)"></line> \
  <line id="line" y1="-3" y2="3" stroke="%23df0000" stroke-linecap="butt" transform="rotate(-45)"></line> \
</svg>');

--icon-tick: url('data:image/svg+xml,\
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="100" height="100" viewBox="-2 -2 16 16"> \
            <path fill="green" stroke-linejoin="round" d="M2 6L1 7l3 4 7-10h-1L4 8z"/> \
</svg>');

The CSS for the form elements:

input[type=text][required],
input[type=email][required],
input[type=password][required],
input[type=tel][required] {
    background-image: var(--icon-required);
    background-position-x: right;
    background-repeat: no-repeat;
    background-size: contain;
}

input:valid {
    --icon-required: var(--icon-tick);
}

The form itself should be in CSS grid:

form {
    align-items: center;
    display: grid;
    grid-gap: var(--form-grid-gap);
    grid-template-columns: var(--form-grid-template-columns);
    margin: auto;
}

The values for the columns can be set to 1fr auto or 1fr with anything such as <p> tags in the form set to span 1/-1. You change the variables in your media queries so that you have the input boxes going full width on mobile and as per above on desktop. You can also change your grid gap on mobile if you wish by using the CSS variables approach.

When the boxes are valid then you should get a green tick instead of the asterisk.

The SVG in CSS is a way of saving the browser from having to do a round trip to the server to get an image of the asterisk. In this way you can fine tune the asterisks, the examples here are at an unusual angle, you can edit this out as the SVG icon above is entirely readable. The viewbox can also be amended to place the asterisk above or below the centre.

Answer 2

write in CSS

.form-group.required .control-label:after {content:"*";color:red;}

and HTML

<div class="form-group required">

    <label class="control-label">Name:</label>

    <input type="text">

</div>

Answer 3

You can achieve the desired result by encapsulating the HTML code in a div tag which contains the "required' class followed by the "form-group" class. *however this works only if you have Bootstrap.

<div class="form-group required">
    <div class="required">
        <label>Name:</label>
        <input type="text">
    </div>
  <div>

Answer 4

This example puts an asterisk symbol in front of a label to denote that particular input as a required field. I set the CSS properties using % and em to makesure my webpage is responsive. You could use px or other absolute units if you want to.

#name {
   display: inline-block;
   margin-left: 40%;
   font-size:25px;
    
}
.nameinput{
   margin-left: 10px;
   font-size:90%;
   width: 17em;
   
}

.nameinput::placeholder {
  font-size: 0.7em;
  vertical-align: middle;
}

#name p{
   margin:0;
   border:0;
   padding:0;
   display:inline-block;
   font-size: 40%;
   vertical-align: super;
}

<label id="name" value="name">
<p>*</p> 
Name:  <input class="nameinput" type="text" placeholder="Enter your name" required>
</label>

Answer 5

What you need is :required selector - it will select all fields with 'required' attribute (so no need to add any additional classes). Then - style inputs according to your needs. You can use ':after' selector and add asterisk in the way suggested among other answers

Answer 6

For those who end up here, but have jQuery:

// javascript / jQuery
$("label.required").append('<span class="red-star"> *</span>')

// css
.red-star { color: red; }