Required field custom validation

I have one form with many input fields. I have put html5 validations

<input type="text" name="topicName" id="topicName" required />

when I submit the form without filling this textbox it shows default message like

"Please fill out this field"

Can anyone please help me to edit this message?

I have a javascript code to edit it, but it's not working

$(document).ready(function() {
    var elements = document.getElementsByName("topicName");
    for (var i = 0; i < elements.length; i++) {
        elements[i].oninvalid = function(e) {
            e.target.setCustomValidity("");
            if (!e.target.validity.valid) {
                e.target.setCustomValidity("Please enter Room Topic Title");
            }
        };
        elements[i].oninput = function(e) {
            e.target.setCustomValidity("");
        };
    }
})

Email custom validations

I have following HTML form

<form id="myform">
    <input id="email" name="email" type="email" />
    <input type="submit" />
</form>

Validation messages I want like.

Required field: Please Enter Email Address
Wrong Email: '[email protected]' is not a Valid Email Address. (here, entered email address displayed in textbox)

I have tried this.

function check(input) {  
    if(input.validity.typeMismatch){  
        input.setCustomValidity("'" + input.value + "' is not a Valid Email Address.");  
    }  
    else {  
        input.setCustomValidity("");  
    }                 
}  

This function is not working properly, Do you have any other way to do this? It would be appreciated.

Code snippet

Since this answer got very much attention, here is a nice configurable snippet I came up with:

/**
  * @author ComFreek <https://stackoverflow.com/users/603003/comfreek>
  * @link https://stackoverflow.com/a/16069817/603003
  * @license MIT 2013-2015 ComFreek
  * @license[dual licensed] CC BY-SA 3.0 2013-2015 ComFreek
  * You MUST retain this license header!
  */
(function (exports) {
    function valOrFunction(val, ctx, args) {
        if (typeof val == "function") {
            return val.apply(ctx, args);
        } else {
            return val;
        }
    }

    function InvalidInputHelper(input, options) {
        input.setCustomValidity(valOrFunction(options.defaultText, window, [input]));

        function changeOrInput() {
            if (input.value == "") {
                input.setCustomValidity(valOrFunction(options.emptyText, window, [input]));
            } else {
                input.setCustomValidity("");
            }
        }

        function invalid() {
            if (input.value == "") {
                input.setCustomValidity(valOrFunction(options.emptyText, window, [input]));
            } else {
               input.setCustomValidity(valOrFunction(options.invalidText, window, [input]));
            }
        }

        input.addEventListener("change", changeOrInput);
        input.addEventListener("input", changeOrInput);
        input.addEventListener("invalid", invalid);
    }
    exports.InvalidInputHelper = InvalidInputHelper;
})(window);

Usage

→ jsFiddle

<input id="email" type="email" required="required" />

InvalidInputHelper(document.getElementById("email"), {
  defaultText: "Please enter an email address!",

  emptyText: "Please enter an email address!",

  invalidText: function (input) {
    return 'The email address "' + input.value + '" is invalid!';
  }
});

More details

• defaultText is displayed initially
• emptyText is displayed when the input is empty (was cleared)
• invalidText is displayed when the input is marked as invalid by the browser (for example when it's not a valid email address)

You can either assign a string or a function to each of the three properties.
If you assign a function, it can accept a reference to the input element (DOM node) and it must return a string which is then displayed as the error message.

Compatibility

Tested in:

• Chrome Canary 47.0.2
• IE 11
• Microsoft Edge (using the up-to-date version as of 28/08/2015)
• Firefox 40.0.3
• Opera 31.0

Old answer

You can see the old revision here: https://stackoverflow.com/revisions/16069817/6

You can simply achieve this using oninvalid attribute, checkout this demo code

<form>
<input type="email" pattern="[^@]*@[^@]" required oninvalid="this.setCustomValidity('Put  here custom message')"/>
<input type="submit"/>
</form>

Codepen Demo: https://codepen.io/akshaykhale1992/pen/yLNvOqP