Change the minimum value:
document.getElementById("myMonth").min = "2020-01";
Click the button to change the value of the min attribute of the month field.
input elements with type=month is not supported in Firefox.
<!DOCTYPE html> <html> <body> Month:/* ww w . ja v a 2 s . co m*/ <input type="month" id="myMonth" min="2014-04" max="2014-09"> <button onclick="myFunction()">Test</button> <p id="demo"></p> <script> function myFunction() { var x = document.getElementById("myMonth").min= "2020-01"; document.getElementById("demo").innerHTML = "The value of the min attribute was changed."; } </script> </body> </html>