Get the width of a password field:
var x = document.getElementById("myPsw").size;
Click the button to display the value of the size attribute.
<!DOCTYPE html> <html> <body> Password: <input type="password" id="myPsw" size="30"> <button onclick="myFunction()">Test</button> <p id="demo"></p> <script> function myFunction() {/*from w w w . j a v a 2s .c o m*/ var x = document.getElementById("myPsw").size; document.getElementById("demo").innerHTML = x; } </script> </body> </html>