With HTML5 url input validation assume url starts with http://

if you don't want the browser validation (it can vary between browsers) you can add the following novalidate attribute

<input type="url" name="someUrl"  formnovalidate="formnovalidate"> 

else you might want to be more transparent about prefixing http:// by simply adding once someone starts to type or even to have http:// already typed into the box on the page load

(credit to editor who rightly points out that novalidate applies to form, while above overrides that, debit to creditor for approach to edit ;)

The code for this should not interrupt the user's action, but should instead wait until the user leaves the form field to check the input text for "http". So use "onblur" instead of "onkeyup".

Then, just see if the string contains "http" using indexOf. If not, it will return -1, which is falsey.

function checkURL (abc) {
  var string = abc.value;
  if (!~string.indexOf("http")) {
    string = "http://" + string;
  }
  abc.value = string;
  return abc
}

<form>
  <input type="url" name="someUrl" onblur="checkURL(this)" />
  <input type="text"/>
</form>

Fiddle

what you guys probably want to use is this:

$(function(){
         $('input[type="url"]').on('blur', function(){
           var string = $(this).val();
           if (!string.match(/^https?:/) && string.length) {
             string = "https://" + string;
              $(this).val(string)
           }
         });
});

this runs on document ready

checks if value is empty or has missing http at the beginning

inserts it in that case on blur

thanks @1j01

you can use

HTML :

<form>
   <input type="url" name="someUrl" onkeyup="checkUR(this)" >
</form>

SCRIPT:

function checkUR(abc){
    string = abc.value
    if(!(/^http:\/\//.test(string))){
        string = "http://" + string;
    }
    abc.value=string
}

example

I hope it will help