how to check the email validation in javascript on form submit code example

Example 1: email validation in javascript

/* JavaScript: validating email address */

isValidEmail("[email protected]"); // true

function isValidEmail(email) {
	var emailRegex = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
	return !!email && typeof email === 'string'
		&& email.match(emailformat)};
};

Example 2: Email validation using javascript

function checkEmail() {

    var email = document.getElementById('txtEmail');
    var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;

    if (!filter.test(email.value)) {
    alert('Please provide a valid email address');
    email.focus;
    return false;
 }
}

- Call the function on Email textbox