Year validation in Javascript

Question

I want to do year validation whre it should be only numeric and Its should be 4 digit long and between 1920 to current year for that I have create Javascript function as follows:

function yearValidation(year) {
 var text = /^[0-9]+$/;
 if (year != 0) {
 if ((year != "") && (!text.test(year))) {
 alert("Please Enter Numeric Values Only");
 return false;
 }
 if (year.length != 4) {
 alert("Year is not proper. Please check");
 return false;
 }
 var current_year=new Date().getFullYear();
 if((year < 1920) || (year > current_year))
 {
 alert("Year should be in range 1920 to current year");
 return false;
 }
 return true;
 }

and called it on onkeypress="return yearValidation(this.value)"

But when I enter 1 it gives me alert:

Year should be in range 1920 to current year

• elclanrs: Well, 1 it's not empty, it's not 4, and it's less than 1920 so it's seems correct.
• Amadan: Do it onchange instead of onkeypress.
• Mithun Satheesh: do it onBlur of your text input.

Answer 1

Applying two event should solve the problem.
HTML:

 <input type="text" 
 onblur="yearValidation(this.value,event)" 
 onkeypress="yearValidation(this.value,event)"
 >

JS:

function yearValidation(year,ev) {
 var text = /^[0-9]+$/;
 if(ev.type=="blur" || year.length==4 && ev.keyCode!=8 && ev.keyCode!=46) {
 if (year != 0) {
 if ((year != "") && (!text.test(year))) {
 alert("Please Enter Numeric Values Only");
 return false;
 }
 if (year.length != 4) {
 alert("Year is not proper. Please check");
 return false;
 }
 var current_year=new Date().getFullYear();
 if((year < 1920) || (year > current_year))
 {
 alert("Year should be in range 1920 to current year");
 return false;
 }
 return true;
 } }
}

Answer 2

Guess it's:

 if (year.length < 4) {

not

if (year.length != 4) {

Answer 3

Or directly in form

<input name="date_check" 
type="text" 
title="Date must be in this case:dd.mm.yy" 
pattern="^[0-9]{1,2}\.[0-9]{2}$" />