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condition on radio button onclick, if false don't check

onclick of one radio button i have to check one condition if true i have to check it or restore to same old status,
html
<input type="radio" name="test" id="radio0" onclick="myFunction()" checked />
<input type="radio" name="test" id="radio1" onclick="myFunction()" />
<input type="radio" name="test" id="radio2" onclick="myFunction()" />
JS
globalCondition = false;
function myFunction()
{
if(globalCondition)
{
//some codes and it will check clicked radio button anyway
}
else
{
return false; // i tried this but its not working
/*here i don't want to check clicked radio button, and previously
checked button should be checked*/
}
}

As I said in comment return in the function will not do anything as you're not returning the function value in the in-line code.
Although the other solutions offered are correct, to keep your code unobtrusive, you should not have inline JS at all (remove the onclick='s).
I realize the question was not tagged jQuery, but maybe it should have been: Instead on onclick you should use a jQuery event handler, selecting only the set of radio buttons.
JSFiddle: http://jsfiddle.net/TrueBlueAussie/KVwL3/1/
globalCondition = false;
$(function(){
$("[name=test]").click(function(e){
if(globalCondition)
{
//some codes and it will check clicked radio button anyway
}
else
{
return false;
// or
e.preventDefault();
/*here i don't want to check clicked radio button, and previously
checked button should be checked*/
}
});
});
Notes:
DOM ready event:
$(function(){ YOUR CODE HERE }); is a shortcut for $(document).ready(function(){ YOUR CODE HERE});
Selectors
If an attribute [] selector = value contains special characters it needs to be quoted:
e.g.
$('[name="IstDynamicModel[SD_WO_CREATE]"]')
There are any number of selectors that will choose just the three radio buttons. As this is a simple one-off connection, at startup, there is no real speed difference between any options, but you would normally try and make the selector specific in ways that might make use of various lookup tables available to the browser:
e.g.
$('input[type=radio][name="IstDynamicModel[SD_WO_CREATE]"]')
This will be slightly faster as it will reduce the slowest check (the name=) to only radio inputs.

try this:
globalCondition = false;
function myFunction(e)
{
if(globalCondition)
{
//some codes and it will check clicked radio button anyway
}
else
{
e.preventDefault();
return false; // i tried this but its not working
/*here i don't want to check clicked radio button, and previously
checked button should be checked*/
}
}

USe like this
<input type="radio" name="test" id="radio1" onclick="return myFunction()" />
javascript
globalCondition = false;
function myFunction(e)
{
if(globalCondition)
{
//some codes and it will check clicked radio button anyway
return true;
}
else
{
return false; // i tried this but its not working
/*here i don't want to check clicked radio button, and previously
checked button should be checked*/
}
}

Call Javascript function only when checkbox is NOT checked

I'm trying to figure out how to call a Javascript function only when a checkbox is NOT checked.
Here is my checkbox:
<input type="checkbox" id="icd" name="icd" value="icd" />
Here is the name of the function:
planhide();

document.getElementById('icd').onchange = function() {
if ( document.getElementById('icd').checked === false ) {
planhide();
}
};​

Include onchange option in the input tag and then add an intermediate function that checks and calls planhide() accordingly as follows:
<input type="checkbox" id="icd" name="icd" value="icd" onchange=check()/>
Then define the check() to do check the state and call the function as follows:
function check()
{
if(document.getElementById("icd").checked==false)
planhide();
}
Also instead of onchange you can also use onclick on the submit button option to call the check() function as like follows:
<input type="button" onclick=check()/>

$(document).ready(function () {
$('#icd').change(function () {
if (!this.checked) {
planhide();
}
});
});

just register an onchange handler on your input, check the 'checked' property when the handler is call, and call the method if checked is false.
Here is a fiddle.

jquery each for all text boxes

I am using following script to bind a keypress event on each textbox so that on reaching the maxlength, focus will switch to next input field. Passing classname as the prarameters to the function.
function autoFocusPhoneFields(txtbox1ID,txtbox2ID) {
$('input.'+txtbox1ID+', input.'+txtbox2ID+'').each(function() {
$(this).bind('keypress', function(){
if(this.value.length == $(this).attr('maxlength')) {
$(this).next('input').focus();
}
});
});
}
$(document).ready(function(){
autoFocusPhoneFields('mobileprefix','mobilecode');
});
As i have mentioned two different input ..it is runnign fine. Butis there any way around so that it will get the classnames and runs through each input box to attach keypress event.

If I understand you correctly, you want to attach the same event handler to every input field? Just use the selector:
$(':text')
(for all input type="text") fields.
So just change
$('input.'+txtbox1ID+', input.'+txtbox2ID+'').each(function() {
to:
$(':text').each(function() {

If I get you correctly you just need to use type selector for input. You can also get rid of calling each to iterate thru inputs since binding event to multiply elements interates via them. So you can change your code into something like following:
var autoFocusPhoneFields = function () {
$('input:text').keypress(function() {
if(this.value.length == $(this).attr('maxlength'))
$(this).next('input').focus();
});
}
$(autoFocusPhoneFields);

This works fine.
HTML
<input id="one" class="inp" maxlength="5" />
<input id="two" class="inp" maxlength="3" />
<input id="three" class="inp" maxlength="2" />
JS Part
$(function(){
var onpress = function(){
var val = $(this).val();
var next_input = $(this).next('input');
var mx = $(this).attr('maxlength');
try {
mx = Number(mx);
if (next_input.length >= 1 && val.length >= mx){
next_input.focus();
}
} catch(x){}
}
$('input.inp').bind('keypress', onpress);
});

check/uncheck radio input with javascript

I have a radio input group. If a radio is checked and I click again it becomes unchecked.
Is there a way to get the previous status of the radio onClick event?
<input name="options" type="radio" onClick="resetMeIfChecked()">
<input name="options" type="radio" onClick="resetMeIfChecked()">
<input name="options" type="radio" onClick="resetMeIfChecked()">

jQuery edition
// bind to retrieve old status
$('input[type="radio"]').mousedown(function() {
// if it was checked before
if(this.checked) {
// bind event to reset state after click is completed
$(this).mouseup(function() {
// bind param, because "this" will point somewhere else in setTimeout
var radio = this;
// apparently if you do it immediatelly, it will be overriden, hence wait a tiny bit
setTimeout(function() {
radio.checked = false;
}, 5);
// don't handle mouseup anymore unless bound again
$(this).unbind('mouseup');
});
}
});
But again, this is not how radio buttons are intended to be used. I think you'd be better of with a set checkbox'es where you could uncheck all other checkboxes than the current clicked (hence always max 1 selected)
A working example

I use this. You simply store the pre-click value and ! it into the value.
<input type=radio name="myoptions" value="1"
onmousedown="this.tag = this.checked;" onclick="this.checked = !this.tag;">

This behavior is not the expected one for radio buttons and I don't recommend it at all. Try to find another way of achieving this. Use another widget or another option to reset the field value:
http://jsfiddle.net/marcosfromero/rRTE8/

try this:
function resetMeIfChecked(radio){
if(radio.checked && radio.value == window.lastrv){
$(radio).removeAttr('checked');
window.lastrv = 0;
}
else
window.lastrv = radio.value;
}
<input value="1" name="options" checked="checked" type="radio" onClick="resetMeIfChecked(this)" />A
<input value="2" name="options" type="radio" onClick="resetMeIfChecked(this)" />B
<input value="3" name="options" type="radio" onClick="resetMeIfChecked(this)" />C

Its quite simple. Just follow the simple example and
var rdblength=document.formname.elementname.length;
alert('length='+rdblength);
for(i=0;i<rdblength;i++){
document.formname.elementname[i].checked=false;
}
Just find the length and make every index checked=true/false.
Ping me at:-
http://manojbardhan2009.blogspot.com

I had the same problem and figured it out. None of the answers above work exactly as I wanted - most of them require an additional button to reset the radio. The goal was to uncheck radio by clicking on the radio itself.
Here's the fiddle: http://jsfiddle.net/MEk5Q/1/
The problem was very complicated because the radio button value changes BEFORE the click event fires so when we're listening to the event we can't tell if the radio button was already checked or not. In both cases it is already checked.
Another approach was to listen to mousedown event. Unlike click, it fires before changing radio checked attribute but unchecking it inside event handler gives us nothing since it is checked back again during mouseup event.
My answer is a little ugly workaround so I generally don't suggest it to others and I'll probably abandon it myself. It works but it involves 20ms timeout function which I'm not fond of in cases like this.
Here is the code explanation:
$('input[type="radio"]').on('mousedown', function() {
if (this.checked) { //on mousedown we can easily determine if the radio is already checked
this.dataset.check = '1'; //if so, we set a custom attribute (in DOM it would be data-check="1")
}
}).on('mouseup', function() {
if (this.dataset.check) { //then on mouseup we determine if the radio was just meant to be unchecked
var radio = this;
setTimeout(function() {radio.checked = false;}, 20); //we give it a 20ms delay because radio checking fires right after mouseup event
delete this.dataset.check; //get rid of our custom attribute
}
});
As a timeout function I could use a string (less writing) but as far as I know it would be eval'ed. Though I don't trust eval function, I prefered anonymous function.
One more thing - one could ask why spreading the code into two separate event handlers while we can fire the timeout function on mousedown? Well, what if someone press the mouse on a radio and holds it for a few secs or even someone is simply a very slow person ;). Generally, with this solution we omit the problem of lag between mousedown and mouseup.
If you need some more info about dataset, here's the MDN reference:
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.dataset
This property came with HTML5 and might be not cross-browser, I guess, so if you want 100% compatibility, replace it with any other solution that'll contain the data, you name it.
Sorry about jQuery here and there but I hope you're fine with it - it was much easier that way.
Hope you'll enjoy it.

$('input[type="radio"]').on("mousedown", function () {
if (this.checked) {
$(this).one("click", function () {
this.checked = false;
});
}
});

I was never too happy about being forced to aim at that tiny radio button, so I came up with a larger target AND a way to turn a radio group off without resorting to anything that would upset the HTML / JavaScript purists.
The technique relies on not molesting the radio buttons at all via event handlers, but checking for a readonly proxy for each one instead. Everything is contained in what's below in pure JavaScript using a radio group to select a type of cheese, or no cheese at all.
I purposely used no styling in this example to avoid that added layer. The dump button will tell you what the three checked states are, so use it to interrogate what happened after hitting the radio or text input elements. For example simplicity I used a global to remember the former state, but a more elegant method is to use a dataset, which I what I use in the real code of my application.
<!DOCTYPE html>
<html>
<head>
<title>Uncheck a radio button</title>
<script>
function attachEventListener(target, eventType, functionRef, capture) {
"use strict";
if (typeof target.addEventListener !== 'undefined') {
// Most modern browsers
target.addEventListener(eventType, functionRef, capture);
} else if (typeof target.attachEvent !== 'undefined') {
// IE
target.attachEvent('on' + eventType, functionRef);
} else {
eventType = 'on' + eventType;
if (typeof target[eventType] === 'function') {
var oldListener = target[eventType];
target[eventType] = function() {
oldListener();
return functionRef();
};
} else {
target[eventType] = functionRef;
}
}
}
</script>
</head>
<body>
<form>
<input id="Cheddar-radio" class="radio" type="radio" name="Cheeses-0" value="Cheddar Cheese" tabindex="-1"></input>
<input id="Cheddar-text" type="text" readonly value="Cheddar Cheese" tabindex="-1"></input><br>
<input id="Swiss-radio" class="radio" type="radio" name="Cheeses-0" value="Swiss Cheese" tabindex="-1"></input>
<input id="Swiss-text" type="text" readonly value="Swiss Cheese" tabindex="-1"></input><br>
<input id="American-radio" class="radio" type="radio" name="Cheeses-0" value="American Cheese" tabindex="-1"></input>
<input id="American-text" type="text" readonly value="American Cheese" tabindex="-1"></input><br><br>
<input onclick="dumpStates()" type="button" name="button" value="dump" tabindex="-1"></input>
</form>
<script>
window.onload = addRadioListeners;
function addRadioListeners() { // But do it on the -text elements.
attachEventListener(document.getElementById('Cheddar-text') , 'mousedown', rememberCurrentState, false);
attachEventListener(document.getElementById('Swiss-text') , 'mousedown', rememberCurrentState, false);
attachEventListener(document.getElementById('American-text'), 'mousedown', rememberCurrentState, false);
attachEventListener(document.getElementById('Cheddar-text') , 'mouseup', checkNewState, false);
attachEventListener(document.getElementById('Swiss-text') , 'mouseup', checkNewState, false);
attachEventListener(document.getElementById('American-text'), 'mouseup', checkNewState, false);
}
function dumpStates() {
console.log(document.getElementById('Cheddar-radio').checked +
' ' + document.getElementById('Swiss-radio').checked +
' ' + document.getElementById('American-radio').checked);
}
var elementWasChecked; // Global - Could just as well use a dataset attribute
// on either the -radio or -text element and check it instead.
function rememberCurrentState(event) {
var element;
var radioElement;
element = event.target;
radioElement = document.getElementById(element.id.replace(/text/,'radio'));
elementWasChecked = radioElement.checked;
radioElement.checked = true;
}
function checkNewState(event) {
var element;
var radioElement;
element = event.target;
radioElement = document.getElementById(element.id.replace(/text/,'radio'));
var currentState = radioElement.checked;
if (elementWasChecked === true && currentState === true) {
console.log('Changing ' + radioElement.id + ' to false.');
radioElement.checked = false;
}
};
</script>
</body>
</html>
If you click on the radio buttons they work as expected. If you click on the text items next to each, they are a proxy for the radio buttons with one exception. If you click on a text item that has an associated radio button that's already checked, it will uncheck it. Therefore, the text proxy's are event triggered, and not the radio buttons.
The added benefit is that you can now hit the larger text target too.

If you want to make it simple and wouldn't mind using a double-click event try something like this:
<input name="options" type="radio" ondblclick="this.checked=false;">

#jerjer's answer is almost perfect, but radios can be switched also by arrows if the radio group has the focus (so mousedown event is not enough). Alas, the radio group also gets checked when activated by focus shift (Tab), which can undesirably check one option. Therefore space should uncheck the focused radio, just like the checkbox behavior.
This code fixes that for all radios (Most credit still goes to jerjer):
window.addEventListener("DOMContentLoaded", function() {
var radios = document.querySelectorAll("input[type=radio]");
for(var i=0; i<radios.length; ++i) {
radios[i].addEventListener("click", function(e) {
if(e.target.checked && e.target.value == window.lastrv){
e.target.checked = false;
window.lastrv = 0;
}
else
window.lastrv = e.target.value;
});
radios[i].addEventListener("keypress", function(e) {
if(e.keyCode==32) e.target.click();
});
}
});

Given a checkbox object output its value

I have a page that has a number of checkboxes in it. I would like to write a function that will be called when the ckeckbox is clicked, that determines if the checkbox is checked or not.
<input type="checkbox" onclick="toggleVis('id', this);"/> ID
<input type="checkbox" onclick="toggleVis('edit', this);" checked="checked"/> Edit
<input type="checkbox" onclick="toggleVis('last', this);"/> Last
Note some checkboxes start checked.
I figured that there must be a way to do this based on a reference passed, so I passed the this value as a parameter.
function toggleVis(name, checkbox)
{
//if(checkbox.checked())
console.log('checked');
if($('.'+name).css('display') != "none")
$('.'+name).css('display', 'none');
else
$('.'+name).css('display', 'table-cell');
}
I am open to use jQuery.

You were close.
if(checkbox.checked) {
console.log('checked');
//...
}
There's no checked() method, but there is a checked property. Note that your code may only work on clicks. Perhaps onchange would be better?

Look at the checkboxobj.checked property (instead of calling it like a function). In your case, you could reference if (checkbox.checked) { ... }. More information can be found on this website

If you wanted to do this with jQuery you might try the following. Note that I'm binding to the checkbox instead of including the 'onclick' or 'onchange' directly on the HTML element.
$('[type=checkbox]').click(function(){
if( $(this).attr('checked') ){
console.log('checked');
if($('.'+$(this).attr('name')).css('display') != "none") {
$('.'+$(this).attr('name')).css('display', 'none');
} else {
$('.'+$(this).attr('name')).css('display', 'table-cell');
}
}
});

And a JQuery-based solution:
var checked = $(checkbox).is(':checked');
Helpful if you want to find the checkbox first by some JQ selector.

<input type="checkbox" class="checkthis"> ID
<input type="checkbox" class="checkthis" checked="checked"> Edit
<input type="checkbox" class="checkthis"> Last
$(input.checkthis).click(function() {
if($(this).is(':checked') {
// do checked stuuf
} else {
// do not checked stuff
}
});