I’m having some strange problem with my JS program. I had this working properly but for some reason it’s no longer working. I just want to find the value of the radio button (which one is selected) and return it to a variable. For some reason it keeps returning undefined.
Here is my code:
function findSelection(field) {
var test = 'document.theForm.' + field;
var sizes = test;
alert(sizes);
for (i=0; i < sizes.length; i++) {
if (sizes[i].checked==true) {
alert(sizes[i].value + ' you got a value');
return sizes[i].value;
}
}
}
submitForm:
function submitForm() {
var genderS = findSelection("genderS");
alert(genderS);
}
HTML:
<form action="#n" name="theForm">
<label for="gender">Gender: </label>
<input type="radio" name="genderS" value="1" checked> Male
<input type="radio" name="genderS" value="0" > Female<br><br>
Search
</form>
This works with any explorer.
document.querySelector('input[name="genderS"]:checked').value;
This is a simple way to get the value of any input type.
You also do not need to include jQuery path.
You can do something like this:
var radios = document.getElementsByName('genderS');
for (var i = 0, length = radios.length; i < length; i++) {
if (radios[i].checked) {
// do whatever you want with the checked radio
alert(radios[i].value);
// only one radio can be logically checked, don't check the rest
break;
}
}
<label for="gender">Gender: </label>
<input type="radio" name="genderS" value="1" checked="checked">Male</input>
<input type="radio" name="genderS" value="0">Female</input>
jsfiddle
Edit: Thanks HATCHA and jpsetung for your edit suggestions.
document.forms.your-form-name.elements.radio-button-name.value
Since jQuery 1.8, the correct syntax for the query is
$('input[name="genderS"]:checked').val();
Not $('input[#name="genderS"]:checked').val(); anymore, which was working in jQuery 1.7 (with the #).
ECMAScript 6 version
let genderS = Array.from(document.getElementsByName("genderS")).find(r => r.checked).value;
Here's a nice way to get the checked radio button's value with plain JavaScript:
const form = document.forms.demo;
const checked = form.querySelector('input[name=characters]:checked');
// log out the value from the :checked radio
console.log(checked.value);
Source: https://ultimatecourses.com/blog/get-value-checked-radio-buttons
Using this HTML:
<form name="demo">
<label>
Mario
<input type="radio" value="mario" name="characters" checked>
</label>
<label>
Luigi
<input type="radio" value="luigi" name="characters">
</label>
<label>
Toad
<input type="radio" value="toad" name="characters">
</label>
</form>
You could also use Array Find the checked property to find the checked item:
Array.from(form.elements.characters).find(radio => radio.checked);
In case someone was looking for an answer and landed here like me, from Chrome 34 and Firefox 33 you can do the following:
var form = document.theForm;
var radios = form.elements['genderS'];
alert(radios.value);
or simpler:
alert(document.theForm.genderS.value);
refrence: https://developer.mozilla.org/en-US/docs/Web/API/RadioNodeList/value
Edit:
As said by Chips_100 you should use :
var sizes = document.theForm[field];
directly without using the test variable.
Old answer:
Shouldn't you eval like this ?
var sizes = eval(test);
I don't know how that works, but to me you're only copying a string.
Try this
function findSelection(field) {
var test = document.getElementsByName(field);
var sizes = test.length;
alert(sizes);
for (i=0; i < sizes; i++) {
if (test[i].checked==true) {
alert(test[i].value + ' you got a value');
return test[i].value;
}
}
}
function submitForm() {
var genderS = findSelection("genderS");
alert(genderS);
return false;
}
A fiddle here.
This is pure JavaScript, based on the answer by #Fontas but with safety code to return an empty string (and avoid a TypeError) if there isn't a selected radio button:
var genderSRadio = document.querySelector("input[name=genderS]:checked");
var genderSValue = genderSRadio ? genderSRadio.value : "";
The code breaks down like this:
Line 1: get a reference to the control that (a) is an <input> type, (b) has a name attribute of genderS, and (c) is checked.
Line 2: If there is such a control, return its value. If there isn't, return an empty string. The genderSRadio variable is truthy if Line 1 finds the control and null/falsey if it doesn't.
For JQuery, use #jbabey's answer, and note that if there isn't a selected radio button it will return undefined.
First, shoutout to ashraf aaref, who's answer I would like to expand a little.
As MDN Web Docs suggest, using RadioNodeList is the preferred way to go:
// Get the form
const form = document.forms[0];
// Get the form's radio buttons
const radios = form.elements['color'];
// You can also easily get the selected value
console.log(radios.value);
// Set the "red" option as the value, i.e. select it
radios.value = 'red';
One might however also select the form via querySelector, which works fine too:
const form = document.querySelector('form[name="somename"]')
However, selecting the radios directly will not work, because it returns a simple NodeList.
document.querySelectorAll('input[name="color"]')
// Returns: NodeList [ input, input ]
While selecting the form first returns a RadioNodeList
document.forms[0].elements['color']
// document.forms[0].color # Shortcut variant
// document.forms[0].elements['complex[naming]'] # Note: shortcuts do not work well with complex field names, thus `elements` for a more programmatic aproach
// Returns: RadioNodeList { 0: input, 1: input, value: "red", length: 2 }
This is why you have to select the form first and then call the elements Method. Aside from all the input Nodes, the RadioNodeList also includes a property value, which enables this simple manipulation.
Reference: https://developer.mozilla.org/en-US/docs/Web/API/RadioNodeList/value
Here is an Example for Radios where no Checked="checked" attribute is used
function test() {
var radios = document.getElementsByName("radiotest");
var found = 1;
for (var i = 0; i < radios.length; i++) {
if (radios[i].checked) {
alert(radios[i].value);
found = 0;
break;
}
}
if(found == 1)
{
alert("Please Select Radio");
}
}
DEMO : http://jsfiddle.net/ipsjolly/hgdWp/2/ [Click Find without selecting any Radio]
Source (from my blog): http://bloggerplugnplay.blogspot.in/2013/01/validateget-checked-radio-value-in.html
Putting Ed Gibbs' answer into a general function:
function findSelection(rad_name) {
const rad_val = document.querySelector('input[name=' + rad_name + ']:checked');
return (rad_val ? rad_val.value : "");
}
Then you can do findSelection("genderS");
lets suppose you need to place different rows of radio buttons in a form, each with separate attribute names ('option1','option2' etc) but the same class name. Perhaps you need them in multiple rows where they will each submit a value based on a scale of 1 to 5 pertaining to a question. you can write your javascript like so:
<script type="text/javascript">
var ratings = document.getElementsByClassName('ratings'); // we access all our radio buttons elements by class name
var radios="";
var i;
for(i=0;i<ratings.length;i++){
ratings[i].onclick=function(){
var result = 0;
radios = document.querySelectorAll("input[class=ratings]:checked");
for(j=0;j<radios.length;j++){
result = result + + radios[j].value;
}
console.log(result);
document.getElementById('overall-average-rating').innerHTML = result; // this row displays your total rating
}
}
</script>
I would also insert the final output into a hidden form element to be submitted together with the form.
I realize this is extremely old, but it can now be done in a single line
function findSelection(name) {
return document.querySelector(`[name="${name}"]:checked`).value
}
I prefer to use a formdata object as it represents the value that should be send if the form was submitted.
Note that it shows a snapshot of the form values. If you change the value, you need to recreate the FormData object. If you want to see the state change of the radio, you need to subscribe to the change event change event demo
Demo:
let formData = new FormData(document.querySelector("form"));
console.log(`The value is: ${formData.get("choice")}`);
<form>
<p>Pizza crust:</p>
<p>
<input type="radio" name="choice" value="regular" >
<label for="choice1id">Regular crust</label>
</p>
<p>
<input type="radio" name="choice" value="deep" checked >
<label for="choice2id">Deep dish</label>
</p>
</form>
If it is possible for you to assign a Id for your form element(), this way can be considered as a safe alternative way (specially when radio group element name is not unique in document):
function findSelection(field) {
var formInputElements = document.getElementById("yourFormId").getElementsByTagName("input");
alert(formInputElements);
for (i=0; i < formInputElements.length; i++) {
if ((formInputElements[i].type == "radio") && (formInputElements[i].name == field) && (formInputElements[i].checked)) {
alert(formInputElements[i].value + ' you got a value');
return formInputElements[i].value;
}
}
}
HTML:
<form action="#n" name="theForm" id="yourFormId">
I like to use brackets to get value from input, its way more clear than using dots.
document.forms['form_name']['input_name'].value;
var value = $('input:radio[name="radiogroupname"]:checked').val();
This is my first time posting here since I haven't been able to find a specific answer for my question anywhere so apologies if I'm doing something wrong.
Anyway, I wanted to know if there was a way to convert text from a form input to a string and grab a substring of that text?
For example if I have a form input like this:
<form onsubmit="return formValidation()">
<input type="text" name="foo">
</form>
Can I grab whatever is typed into that input like so?
function myFunction() {
var string = document.getElementByName('foo').value;
// Code converting the selected element to a string
var index = string.substring(0, 2);
// Rest of code
}
I have little experience in JavaScript so I'm confused on how to convert an element to string. jQuery solutions are welcome.
I wanted to do this for an ID number validation on a form, which basically checks the first two indexes of an 8-digit ID number to see if it's a known ID number in my school district.
Thanks!
EDIT:
Okay so since people actually saw this, could anyone tell me what's wrong with this code? It's returning false even for numbers starting with the numbers here.
function formValidation() {
var idInput = document.getElementsByName('idNumber')[0].value;
var idNumber = idInput.substring(0, 2);
if(idNumber === "71" || idNumber === "81" || idNumber === "53") {
alert("Your form has been submitted. You will now be redirected to a confirmation page.");
return true;
} else {
alert("Please input a valid ID number. If the first two integers of your ID do not match the school district standard, contact a club leader.");
return false;
}
}
Is the method I'm using to compare strings wrong?
Problem is: document.getElementByName('foo').value, you have missed s
document.getElementsByName('foo')
^
document.getElementsByName('foo') gives you NodeList, not just a single HtmlElement,
Use instead:
document.getElementsByName('foo')[0].value;
Edited: Have a look at below functional code.
function formValidation() {
var idInput = document.getElementsByName('idNumber')[0].value;
var idNumber = idInput.substring(0, 2);
if (idNumber === "71" || idNumber === "81" || idNumber === "53") {
alert("Your form has been submitted. You will now be redirected to a confirmation page.");
return true;
} else {
alert("Please input a valid ID number. If the first two integers of your ID do not match the school district standard, contact a club leader.");
return false;
}
}
<form onsubmit="return formValidation();">
<input type="text" name="idNumber" autofocus="" value="71456" maxlength="8" />
</form>
I have 350 text inputs in the form. I want to control those for empty or not. I know for one input eg:
var ism=document.getElementById('inputtext').value;
if(ism.length==0){
return false;
}
But I have inputs :
<input type="text" name="inputtext[]"/>
What I do ?
You may want to consider the HTML 5 way; adding the required attribute to prevent form submission with empty inputs
<input type="text" required />
Trying to submit without putting anything in this will cause a message to be shown and submission prevented
Any method you choose should still have server-side validation
You check all of them I suppose ?
var inputs = document.querySelectorAll('[name="inputtext[]"]'),
isEmpty = false;
for (var i=inputs.length; i--;) {
if ( inputs[i].value.length === 0 ) {
isEmpty = true;
break;
}
}
I have this input text which have a name="quiztxtBox[]", as you can see, it is an array. I want to change the color of the bg of the textbox if the value of a certain textbox is null.
var quiztxtBox = document.getElementById('quiztxtBox[]');
for (i=0; i<quiztxtBox.length; i++)
{
if (quiztxtBox[i].value == "")
{
alert('Either question or answer is empty.');
quiztxtBox[i].focus();
quiztxtBox[i].css({"background-color":"#f6d9d4"});
return false;
}
}
You're using .css() which is a jQuery function.
You should either include jQuery on your page, add cast your DOM element to a jQuery object and apply the the .css() function like so
Also you should be using getElementsByName
$(quiztxtBox[i]).css({..});
or just use vanilla JS as shown below
var quiztxtBox = document.getElementByName('quiztxtBox[]');
for (i=0; i<quiztxtBox.length; i++) {
if (quiztxtBox[i].value === "") {
alert('Either question or answer is empty.');
quiztxtBox[i].focus();
quiztxtBox[i].style.backgroundColor = '#f6d9d4'; // this line
}
}
DEMO
I am not sure If your approach is correct, getElementById always returns one element and no collections, perhaps it would be better if you could get the collection of textboxes using
document.getElementsByName('quiztxtBox')
But remember you might have to update the name attribute of all your textboxes to something like
<input name="quiztxtBox" value="yourvalue" id="someuniquestuff1" />
<input name="quiztxtBox" value="yourvalue" id="someuniquestuff2" />
<input name="quiztxtBox" value="yourvalue" id="someuniquestuff3" />
<input name="quiztxtBox" value="yourvalue" id="someuniquestuff4" />
Thanks
I need some help with something... say I have the following form...
<form name="" id="" method="" action="">
<input type="text" id="text1" name="text1" />
<br />
<br />
<input type="text" id="text2" name="text2" />
<br />
<br />
<input type="text" id="text3" name="text3" />
<br />
<br />
<input type="text" id="text4" name="text4" />
<br />
<br />
<input type="submit" value="let's go" disabled="disabled" />
</form>
Now I want to have a simple script to enable the submit when the values of the text boxes are not an empty string or null...
So I have something like this.. which I will bind to the window.onload
function enableButton(){
var formitemsArray = ['text1','text2','text3','text4'],
i;
// Loop through all items
for(i=0;i<formitemsArray.length;i++){
// validate the length on the keypress...
formitemsArray.onkeypress = function(){
// loop through all the items again
for(j=0;j<formitemsArray.length;j++){
if(formitemsArray[j] == "" || formitemsArray[j] == null ){
// return false or something???
}else{
document.getElementById("submitButton").disabled = false;
}
}
}
}
}
Now I think I'm on the right lines to a solution but I'm getting lost when trying to make sure that all the items are greater than a zero length string as I'm returning false too soon. Can someone set me straight please?
Welcome to event bubbling!
This does the following: listen to an event (onkeypress) on the whole element and all its children! Which means you can do the following:
document.getElementById('form-id').onkeypress = function(e) {
var text1 = document.getElementById('text1'),
text2 = document.getElementById('text2'),
text3 = document.getElementById('text3'),
text4 = document.getElementById('text4')
if (text1.value.length > 0 &&
text2.value.length > 0 &&
text3.value.length > 0 &&
text4.value.length > 0) {
document.getElementById('submit-button').disabled = false
}
// As an aside, for later: if you want to get the element
// that triggered the event, you have to do the following
// to be cross-browser:
var evt = e || window.event, // IE doesn't get the event passed by argument
target = e.target || e.srcElement // 'target' is official, old versions of FF used 'srcElement'
// With the 'target' variable, you can now play.
}
There is another more generic solution, but it might not fit your needs (note that it requires a forEach shim:
// Declare a counter variable
var count = 0
document.getElementById('form-id').onkeypress = function(e) {
// Get all the inputs!
var inputs = this.getElementsByTagName('input')
// Now loop through all those inputs
// Since a NodeList doesn't have the forEach method, let's borrow it from an array!
[].forEach.call(inputs, loopThroughInputs)
}
function loopThroughInputs(input) {
// First check the type of the input
if (input.type === 'text') {
// If the value is correct, increase the counter
if (input.value.length > 0) {
count++
}
// If the 4 inputs have increased the counter, it's alright!
if (count === 4) {
document.getElementById('submit-button').disabled = false
}
}
}
And now this code was proposed by #Esailija, and it is way better and cleaner. However, it also requires ES5-Shim (for the every method):
document.getElementById('form-id').onkeypress = function(e) {
var inputs = [].slice.call( this.querySelectorAll( '[type=text]') );
document.getElementById('submit-button').disabled = !inputs.every(function(input){
return !!input.value;
});
}
(This guy is brillant, just don't tell him)
There are a few ways you can do this... One would be to keep the button enabled but use javascript to check the validity of the form data upon submission. The benefit to this is that the validation code is only run once, when the user clicks submit and is expecting his data to be validated (at least I do) .
function validateForm() {
var formElement = document.forms[0]; // you didn't give me a name
for(var i = 0, l = formElement.elements.length; i < l; i++ ) {
if( formElement.elements[i].value.length === 0 ) {
return false;
}
return true;
}
}
The other way is live validation, which would validate each input onBlur (focus lost). This method has the benefit of showing the user in real time what values are bad, however this can be very resource heavy depending on the number of form elements and the way you introduce the check.
Personally I would go with my first suggestion; however with that said if you choose to validate each element, I would do so like this:
var formElement = document.forms[0]; // you didn't give me a name
for(var i = 0, l = formElement.elements.length; i < l; i++ ) {
formElement.elements[i].addEventListener('blur', function() {
if( this.value.length === 0 ) {
alert('this input is invalid');
}
}, false);
}
The latter method also requires you hold onto a 'state' variable to determine whether or not the form is valid upon submission, or check all the values again.
Hope this sheds some light, and I hope my code examples help some.
If possible use jquery validation plugin instead of re-inventing the code, http://docs.jquery.com/Plugins/Validation its so easy to use.
In this jsfiddle you'll find a way to monitor the progress of form contents. If all the field conditions are fulfilled, a submit button is shown. Maybe it's useful for you. Bare in mind that client side checking of a form may be tampered with, so you always need a server side check too, if your data need to adhere to certain requirements. In other words: client side form checks are merely usability enhancements.