Change the value of the password field:
document.getElementById("myPsw").value = "NewPassword123";
<!DOCTYPE html> <html> <body> <form> Password: <input type="password" id="myPsw"> </form><p id="demo"></p> <button onclick="display()">Display value</button> <button onclick="change()">Change value</button> <script> function display() { var x = document.getElementById("myPsw").value; document.getElementById("demo").innerHTML = "The value of the password field is: " + x; } function change() {//from w ww . j a v a 2s .c o m var x = document.getElementById("myPsw").value = "NewPassword123"; document.getElementById("demo").innerHTML = "The value was changed to: " + x; } </script> </body> </html>