Javascript functions for form fields

4.14 (21 votes)

A number of useful functions for accessing various properties and values of form fields.

Getting the selected index and value from a select list

function getValues(){
var dd = document.getElementById('dropdown');
theindex = dd.options[dd.selectedIndex].value;
thevalue = dd.options[dd.selectedIndex].text;
var span = document.getElementById('span1');
span.innerHTML = '  Selected Index: ' + theindex + 
	', Selected Value: ' + thevalue
}

Detect which checkbox was ticked or unticked, and an array of selected values

function getchk(val){
var output = 'You clicked ' + val + ' Selected: ';
for(var i = 0; i < document.forms[0].check.length; i++){
	if(document.forms[0].check[i].checked)
	output += document.forms[0].check[i].value + ' ';
	}
document.getElementById('span2').innerHTML = output;
}

1
2
3
4

Get the text and number of characters from a text box

function getText(){
var txt = document.getElementById('txt');
var output = txt.value;
var length = output.length;
document.getElementById('span3').innerHTML = 'Count: ' + length
	+ ' Text: ' + output;
}

You might also like...

Date Posted:
Last Updated:
Posted by:
Total Views to date: 11195

3 Comments

- Deep

I have a form which ask for YEAR. How can I restrict user to only allow to input numbers.

I have put a validation which doesn't allow non-numeric but it is tested after the form is POSTed.

Any suggestion for suppressing the non-numeric keys in "NUMERIC-ONLY" text box ???

- Mike

You should use a Javascript library like jQuery's Validate plug in to manage that kind of thing in the browser. In fact, this whole article is pretty obsolete because jQuery makes the tasks outlined above much easier.

- tiara

verry good

Recent Comments

Gfw 03/02/2017 09:48
In response to Free SSL Certificates On IIS With LetsEncrypt
I have used WinSimple for about the last 9 months - works great. One thing that you want to make of...

Ted Driver 02/02/2017 13:24
In response to Free SSL Certificates On IIS With LetsEncrypt
This looks great is you have command line access to your web server - what about those of us on Is...

Carl T. 06/11/2016 05:43
In response to Server.MapPath Equivalent in ASP.NET Core
Very succinct and easy to follow. Worked perfectly the first time for me. Thanks!!...

Manoj Kulkarni 04/11/2016 05:47
In response to Entity Framework Core DbContext Updated
Great post....

Sivu 19/10/2016 08:21
In response to Entity Framework Core TrackGraph For Disconnected Data
Oh that's very very very nice ! Thanks for the write up Mike, much appreciated for the taking the to...

Mark 12/10/2016 16:42
In response to ASP.NET Web Pages vNext or Razor Pages
Although "Web Pages" was removed from the roadmap, has it just been renamed to "Razor Pages"?...

Satyabrata 12/10/2016 09:20
In response to Entity Framework Core TrackGraph For Disconnected Data
Nice article. Please write more articles featuring ASP.Net web pages. Thank you...

Julian 26/09/2016 14:27
In response to Loading ASP.NET Core MVC Views From A Database Or Other Location
Fantastic, many thanks Mike! Had got half way down this road before finding your article - saved...

Abolfazl Roshanzamir 14/09/2016 05:36
In response to Loading ASP.NET Core MVC Views From A Database Or Other Location
Nice article. Thanke you so much ....

cyrus 02/09/2016 15:12
In response to ASP.NET Web Pages vNext or Razor Pages
I've got some news. As Damian stated in this link: https://github.com/aspnet/Mvc/issues/5208 “We...