Get the legal month intervals:
var x = document.getElementById("myMonth").step;
Click the button to display the value of the step attribute of the month field.
The step property is not supported in Firefox.
<!DOCTYPE html> <html> <body> Month: <input type="month" id="myMonth" step="3"> <button onclick="myFunction()">Test</button> <p id="demo"></p> <script> function myFunction() {/* ww w . jav a 2 s . c o m*/ var x = document.getElementById("myMonth").step; document.getElementById("demo").innerHTML = x; } </script> </body> </html>