I've got the following HTML5 form: http://jsfiddle.net/nfgfP/
<form id="form" onsubmit="return(login())">_x000D_
<input name="username" placeholder="Username" required />_x000D_
<input name="pass" type="password" placeholder="Password" required/>_x000D_
<br/>Remember me: <input type="checkbox" name="remember" value="true" /><br/>_x000D_
<input type="submit" name="submit" value="Log In"/>Currently when I hit enter when they're both blank, a popup box appears saying "Please fill out this field". How would I change that default message to "This field cannot be left blank"?
EDIT: Also note that the type password field's error message is simply *****. To recreate this give the username a value and hit submit.
EDIT: I'm using Chrome 10 for testing. Please do the same
This question is related to
javascript
html
forms
validation
The answer is
It's very simple to control custom messages with the help of the HTML5 oninvalid event
Here is the code:
User ID
<input id="UserID" type="text" required
oninvalid="this.setCustomValidity('User ID is a must')">
Okay, oninvalid works well but it shows error even if user entered valid data. So I have used below to tackle it, hope it will work for you as well,
oninvalid="this.setCustomValidity('Your custom message.')" onkeyup="setCustomValidity('')"
Try this one, its better and tested:
HTML:
<form id="myform">
<input id="email"
oninvalid="InvalidMsg(this);"
oninput="InvalidMsg(this);"
name="email"
type="email"
required="required" />
<input type="submit" />
</form>
JAVASCRIPT:
function InvalidMsg(textbox) {
if (textbox.value === '') {
textbox.setCustomValidity('Required email address');
} else if (textbox.validity.typeMismatch){
textbox.setCustomValidity('please enter a valid email address');
} else {
textbox.setCustomValidity('');
}
return true;
}
Demo:
Can be easily handled by just putting 'title' with the field:
<input type="text" id="username" required title="This field can not be empty" />
The solution for preventing Google Chrome error messages on input each symbol:
<p>Click the 'Submit' button with empty input field and you will see the custom error message. Then put "-" sign in the same input field.</p>_x000D_
<form method="post" action="#">_x000D_
<label for="text_number_1">Here you will see browser's error validation message on input:</label><br>_x000D_
<input id="test_number_1" type="number" min="0" required="true"_x000D_
oninput="this.setCustomValidity('')"_x000D_
oninvalid="this.setCustomValidity('This is my custom message.')"/>_x000D_
<input type="submit"/>_x000D_
</form>_x000D_
_x000D_
<form method="post" action="#">_x000D_
<p></p>_x000D_
<label for="text_number_1">Here you will see no error messages on input:</label><br>_x000D_
<input id="test_number_2" type="number" min="0" required="true"_x000D_
oninput="(function(e){e.setCustomValidity(''); return !e.validity.valid && e.setCustomValidity(' ')})(this)"_x000D_
oninvalid="this.setCustomValidity('This is my custom message.')"/>_x000D_
<input type="submit"/>_x000D_
</form>By setting and unsetting the setCustomValidity in the right time, the validation message will work flawlessly.
<input name="Username" required
oninvalid="this.setCustomValidity('Username cannot be empty.')"
onchange="this.setCustomValidity('')" type="text" />
I used onchange instead of oninput which is more general and occurs when the value is changed in any condition even through JavaScript.
I have a simpler vanilla js only solution:
For checkboxes:
document.getElementById("id").oninvalid = function () {
this.setCustomValidity(this.checked ? '' : 'My message');
};
For inputs:
document.getElementById("id").oninvalid = function () {
this.setCustomValidity(this.value ? '' : 'My message');
};
The easiest and cleanest way I've found is to use a data attribute to store your custom error. Test the node for validity and handle the error by using some custom html. 
le javascript
if(node.validity.patternMismatch)
{
message = node.dataset.patternError;
}
and some super HTML5
<input type="text" id="city" name="city" data-pattern-error="Please use only letters for your city." pattern="[A-z ']*" required>
It's very simple to control custom messages with the help of HTML5 event oninvalid
Here is code:
<input id="UserID" type="text" required="required"
oninvalid="this.setCustomValidity('Witinnovation')"
onvalid="this.setCustomValidity('')">
This is most important:
onvalid="this.setCustomValidity('')"
Note: This no longer works in Chrome, not tested in other browsers. See edits below. This answer is being left here for historical reference.
If you feel that the validation string really should not be set by code, you can set you input element's title attribute to read "This field cannot be left blank". (Works in Chrome 10)
title="This field should not be left blank."
See http://jsfiddle.net/kaleb/nfgfP/8/
And in Firefox, you can add this attribute:
x-moz-errormessage="This field should not be left blank."
Edit
This seems to have changed since I originally wrote this answer. Now adding a title does not change the validity message, it just adds an addendum to the message. The fiddle above still applies.
Edit 2
Chrome now does nothing with the title attribute as of Chrome 51. I am not sure in which version this changed.
I have made a small library to ease changing and translating the error messages. You can even change the texts by error type which is currently not available using title in Chrome or x-moz-errormessage in Firefox. Go check it out on GitHub, and give feedback.
It's used like:
<input type="email" required data-errormessage-value-missing="Please input something">
There's a demo available at jsFiddle.
Here is the code to handle custom error message in HTML5:
<input type="text" id="username" required placeholder="Enter Name"
oninvalid="this.setCustomValidity('Enter User Name Here')"
oninput="this.setCustomValidity('')"/>
This part is important because it hides the error message when the user inputs new data:
oninput="this.setCustomValidity('')"
Adapting Salar's answer to JSX and React, I noticed that React Select doesn't behave just like an <input/> field regarding validation. Apparently, several workarounds are needed to show only the custom message and to keep it from showing at inconvenient times.
I've raised an issue here, if it helps anything. Here is a CodeSandbox with a working example, and the most important code there is reproduced here:
Hello.js
import React, { Component } from "react";
import SelectValid from "./SelectValid";
export default class Hello extends Component {
render() {
return (
<form>
<SelectValid placeholder="this one is optional" />
<SelectValid placeholder="this one is required" required />
<input
required
defaultValue="foo"
onChange={e => e.target.setCustomValidity("")}
onInvalid={e => e.target.setCustomValidity("foo")}
/>
<button>button</button>
</form>
);
}
}
SelectValid.js
import React, { Component } from "react";
import Select from "react-select";
import "react-select/dist/react-select.css";
export default class SelectValid extends Component {
render() {
this.required = !this.props.required
? false
: this.state && this.state.value ? false : true;
let inputProps = undefined;
let onInputChange = undefined;
if (this.props.required) {
inputProps = {
onInvalid: e => e.target.setCustomValidity(this.required ? "foo" : "")
};
onInputChange = value => {
this.selectComponent.input.input.setCustomValidity(
value
? ""
: this.required
? "foo"
: this.selectComponent.props.value ? "" : "foo"
);
return value;
};
}
return (
<Select
onChange={value => {
this.required = !this.props.required ? false : value ? false : true;
let state = this && this.state ? this.state : { value: null };
state.value = value;
this.setState(state);
if (this.props.onChange) {
this.props.onChange();
}
}}
value={this && this.state ? this.state.value : null}
options={[{ label: "yes", value: 1 }, { label: "no", value: 0 }]}
placeholder={this.props.placeholder}
required={this.required}
clearable
searchable
inputProps={inputProps}
ref={input => (this.selectComponent = input)}
onInputChange={onInputChange}
/>
);
}
}
Source: Stackoverflow.com