How to change placeholder with Font-Awesome content using jQuery?

This solution needs only:

  • one line of jQuery
  • CSS property font-family:FontAwesome
  • No HTML at all

You'll need the specific CSS code for the icon prefixed with a \u. Font-Awesome documents only class and unicode. Fortunately, this site has what you need. Here's what it should be in jQuery:

$('.mandatory_field').attr('placeholder', '\uf0a4 Mandatory field');

The only difference between CSS and JavaScript font entities is the u in the second character position for JavaScript.

In the demo, I also added some styles with the ::placeholder pseudo element as a bonus. You can style your placeholders without affecting the user input style.

Demo

$('.mandatory_field').attr('placeholder', '\uf0a4 Mandatory field');
/* With the exception of font-family:FontAwesome everything
|| is optional.
*/

input {
  font: inherit
}

.mandatory_field::-webkit-input-placeholder {
  /* Chrome/Opera/Safari */
  color: red;
  font-family: FontAwesome;
  font-variant: small-caps;
}

.mandatory_field::-moz-placeholder {
  /* Firefox 19+ */
  color: red;
  font-family: FontAwesome;
  font-variant: small-caps;
}

.mandatory_field:-ms-input-placeholder {
  /* IE 10+ */
  color: red;
  font-family: FontAwesome;
  font-variant: small-caps;
}
<link rel="stylesheet" href="https://cdn.jsdelivr.net/fontawesome/4.7.0/css/font-awesome.min.css">

<input type="text" class="mandatory_field form-control" id="affiliation">

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>


You can use a data attribute to store the awesome font symbol you want and use it combined with the text $input.data('placeholder') + ' Mandatory field'.

Code example:

var $input = $('#affiliation'),
    placeholder =  $input.data('placeholder') + ' Mandatory field';
    
$input.attr('placeholder', placeholder);
.mandatory_field {  
  font-family: FontAwesome,"Helvetica Neue",Helvetica,Arial,sans-serif; 
}
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet" integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN" crossorigin="anonymous">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input type="text" data-placeholder="&#xf0a4;" class="mandatory_field form-control" id="affiliation">