Alphanumeric validation in JavaScript is used to make sure that all the characters entered in the specified field must be any alphabet (A-Z or a-z) or any number (0-9).
Regular Expression:
/^[0-9a-zA-Z]+$/
Example:
<!DOCTYPE html> <html lang="en"> <head> <script> function lettersNumbersCheck(name) { var regEx = /^[0-9a-zA-Z]+$/; if(name.value.match(regEx)) { return true; } else { alert("Please enter letters and numbers only."); return false; } } </script> </head> <body> <div class="mail"> <h2>JavaScript Letters Numbers Validation</h2> <form name="form1" action="#"> Name: <input type='text' name='name'/></br></br> <input type="submit" name="submit" value="Submit" onclick="lettersNumbersCheck(document.form1.name)"/> </form> </div> </body> </html>