jquery how to make checkbox always checked - javascript

How can I make a checkbox always be checked, with Jquery 1.4.2 ?
This is my html output from the struts application:
<input type="checkbox" name="helloThere" value="on">
I tried:
$(document).ready(function() {
$('#helloThere').attr('checked', 'checked');
});
JSFIDDLE
http://jsfiddle.net/96p4zg9w/ this shows the current code, I would need the checkbox to load checked.
The props property is not available in JQUERY 1.4.2

your jquery selector is wrong.
You are trying select an element with 'helloThere' id, but your input has not an id attribute.
You can add this attribute to your input field or change jquery selector.
Try one of this tow solutions:
<input type="checkbox" name="helloThere" id="helloThere" value="on">
or
$(document).ready(function() {
$("input[name='helloThere']").attr('checked', 'checked');
});

You need to put your JavaScript inside $(document).ready(). This ensures all of the content you might want to touch has been loaded before you try to change it.
In your scenario then, you would need:
$(document).ready(function() {
$('#helloThere').attr('checked', 'checked');
});
Edit: Your checkbox doesn't have an ID. You need to add an ID of "helloThere" for $('#helloThere') to pick it up. Your fiddle also needs to have jQuery loaded using the menu on the left. Here's a working version: http://jsfiddle.net/96p4zg9w/1/

Check this jsfiddle for a working example of how you can do it using javascript.
If you want to use versions of jQuery below 1.5, you need to do it this way:
$("#checkbox").attr("checked", true);
or
$("#checkbox").attr("checked", "checked");
If you want to select element using the name instead of id, use:
input[name='helloThere']
Hope it useful!

It can be done in three ways. You can use checked in input that will always stay checked.
<input id="myId" type="checkbox" name="name" checked>
Using prop and assume input id is myId
$(document).ready(function() {
$(#myId).prop('checked', true);
});
Before jQuery 1.6 using attr
$(document).ready(function() {
$(#ID).attr('checked','checked');
});

<lable>this will always be checked, even you try to uncheck</lable>:
<input type="checkbox" checked onclick="return false;">

Related

Initially set all checkboxes to checked

I have jquery code that has the ability to set all checkboxes to 'checked' state on the click of a 'check all' checkbox. However, I would like to initially, start a html page by already having all checkboxes checked without having to click on that 'check all' checkbox. Please bear in mind, though, that I would like to keep the 'check all' checkbox since it has the ability to uncheck all checkboxes as well.
Here's my jquery code :
$('.chk_boxes').click(function(){
var chk = $(this).attr('checked')?true:false;
$('.chk_boxes1').attr('checked',chk);
});
If you want to have all your checkboxes checked the moment the page is loaded without the need to click anything, use:
$(document).ready(function(){
$("input:checkbox").prop("checked", "true");
});
Or just generate your HTML input tag like so:
<input type="checkbox" checked="checked" />
Hope this helps!
You could place your checkAll function outside of your click function, call it once the page load and when you click on the check all button
$(document).ready(function(){
checkAll(true);
$('.chk_boxes').click(function(){
var chk = $(this).attr('checked')?true:false;
checkAll(chk)
});
function checkAll(isCheck){
$('.chk_boxes1').attr('checked',isCheck);
}
})
I also like #Univ approach.
Change your original function to:
$('.chk_boxes').click(chkAll());
Create a new function:
function chkAll(){
var chk = $(this).attr('checked')?true:false;
$('.chk_boxes1').attr('checked',chk);
}
Call the new function when document are ready:
$(document).ready(function(){
chkAll();
})
I would just use html attributes
<input name="name" id="id" type="checkbox" checked="checked">
I wouldn't recommend using javascript to set these initial values because it will unnecessarily waste resources in the client machines.

Check a radio button with javascript

For some reason, I can't seem to figure this out.
I have some radio buttons in my html which toggles categories:
<input type="radio" name="main-categories" id="_1234" value="1234" /> // All
<input type="radio" name="main-categories" id="_2345" value="2345" /> // Certain category
<input type="radio" name="main-categories" id="_3456" value="3456" /> // Certain category
<input type="radio" name="main-categories" id="_4567" value="4567" /> // Certain category
The user can select whichever he/she wants, but when an certain event triggers, I want to set 1234 to be set checked radio button, because this is the default checked radio button.
I have tried versions of this (with and without jQuery):
document.getElementById('#_1234').checked = true;
But it doesn't seem to update. I need it to visibly update so the user can see it.
Can anybody help?
EDIT: I'm just tired and overlooked the #, thanks for pointing it out, that and $.prop().
Do not mix CSS/JQuery syntax (# for identifier) with native JS.
Native JS solution:
document.getElementById("_1234").checked = true;
JQuery solution:
$("#_1234").prop("checked", true);
If you want to set the "1234" button, you need to use its "id":
document.getElementById("_1234").checked = true;
When you're using the browser API ("getElementById"), you don't use selector syntax; you just pass the actual "id" value you're looking for. You use selector syntax with jQuery or .querySelector() and .querySelectorAll().
Today, in the year 2016, it is safe to use document.querySelector without knowing the ID (especially if you have more than 2 radio buttons):
document.querySelector("input[name=main-categories]:checked").value
Easiest way would probably be with jQuery, as follows:
$(document).ready(function(){
$("#_1234").attr("checked","checked");
})
This adds a new attribute "checked" (which in HTML does not need a value).
Just remember to include the jQuery library:
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
By using document.getElementById() function you don't have to pass # before element's id.
Code:
document.getElementById('_1234').checked = true;
Demo:
JSFiddle
I was able to select (check) a radio input button by using this Javascript code in Firefox 72, within a Web Extension option page to LOAD the value:
var reloadItem = browser.storage.sync.get('reload_mode');
reloadItem.then((response) => {
if (response["reload_mode"] == "Periodic") {
document.querySelector('input[name=reload_mode][value="Periodic"]').click();
} else if (response["reload_mode"] == "Page Bottom") {
document.querySelector('input[name=reload_mode][value="Page Bottom"]').click();
} else {
document.querySelector('input[name=reload_mode][value="Both"]').click();
}
});
Where the associated code to SAVE the value was:
reload_mode: document.querySelector('input[name=reload_mode]:checked').value
Given HTML like the following:
<input type="radio" id="periodic" name="reload_mode" value="Periodic">
<label for="periodic">Periodic</label><br>
<input type="radio" id="bottom" name="reload_mode" value="Page Bottom">
<label for="bottom">Page Bottom</label><br>
<input type="radio" id="both" name="reload_mode" value="Both">
<label for="both">Both</label></br></br>
It seems the item.checked property of a HTML radio button cannot be changed with JavaScript in Internet Explorer, or in some older browsers.
I also tried setting the "checked" attribute, using:
item.setAttribute("checked", ""); I know the property can be set by default,
but I need just to change the checked attribute at runtime.
As a workarround, I found another method, which could be working. I had called the item.click(); method of a radio button. And the control has been selected. But the control must be already added to the HTML document, in order to receive the click event.

Checkbox irregularities with jQuery

Here's some html:
<form>
<input type="checkbox" id="check-123" />
<input type="text" id="text-123" onchange="doSomething('123')" />
</form>
And here's some javascript:
function doSomething(key)
{
var textbox = $('#text-'+key);
var checkbox = $('#check-'+key);
checkbox.attr('checked',(textbox.val()!="") );
}
My goal here is to check the checkbox anytime there's a value in the text box, and uncheck when that value is removed. This appears to work fine in the html (I can see checked="checked" being added to the checkbox), but the checkbox only appears checked the first time something is entered in the textbox.
Why would a checkbox show unchecked even if checked="checked" was added to the html?
Use element properties rather than attributes to change their state via javascript
checkbox.prop('checked',(textbox.val()!="") );
From the jQuery docs on .attr() and .prop():
As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set. To retrieve and change DOM properties such as the checked, selected, or disabled state of form elements, use the .prop() method.
The emphasis is jQuery's own. Only the checked property will reflect and control the checkbox's current state. The checked attribute shouldn't be used to control the checkbox state.
consider something like:
function doSomething(el) {
el.form['check-' + el.name.split('-')[1]].checked = !!el.value;
}
<form>
<input type="checkbox" name="check-123">
<input type="text" name="text-123" onchange="doSomething(this)">
</form>
I've seen some funny things with the checked attribute in IE8 and lower. In some cases I've had to set both the property and the attribute, even though modern browsers seem to be okay with just adjusting the property:
checkbox.prop('checked',textbox.val()!="");//property
Note, the following is only necessary if you come across any browser related inconsistencies.
if(textbox.val()!="")
{
checkbox.attr('checked','checked');
}
else
{
checkbox.removeAttr('checked');
}

How to check "checkbox" dynamically - jQuery Mobile

With HTML a checkbox is created like this:
<form>
<input type="checkbox" id="category1">Category1<br>
</form>
With javascript we can check the checkbox like this:
$("#category1")[0].checked = true
Now I am trying to create the same page with jquery-mobile. The checkbox looks like this:
<form>
<label>
<input name="checkbox-0 " type="checkbox">Check me
</label>
</form>
Why is there is no id here? Is the name the id? Should I delete the attribute name and create one with the name id?
How can I check this checkbox here with Javascript/jQuery?
I tried the code above, but it doesn't seem to work for this checkbox.
You need to refresh it after changing its' .prop, using .checkboxradio('refresh'). This is the correct way to check checkbox/radio in jQuery Mobile.
Demo
$('.selector').prop('checked', true).checkboxradio('refresh');
Reference: jQuery Mobile API
You can do:
$('input[name="checkbox-0"]').prop("checked", true).checkboxradio('refresh'); //sets the checkbox
var isChecked = $('input[name="checkbox-0"]').prop("checked"); //gets the status
Straight from the jQ Mobile docs:
$("input[type='checkbox']").attr("checked",true);
With the solution from #Omar I get the error:
Uncaught Error: cannot call methods on checkboxradio prior to initialization; attempted to call method 'refresh'
I actually had a flipswitch checkbox:
<div class="some-checkbox-area">
<input type="checkbox" data-role="flipswitch" name="flip-checkbox-lesson-complete"
data-on-text="Complete" data-off-text="Incomplete" data-wrapper-class="custom-size-flipswitch">
</div>
and found the solution was:
$("div.ui-page-active div.some-checkbox-area div.ui-flipswitch input[type=checkbox]").attr("checked", true).flipswitch( "refresh" )
Notes
I don't usually specify ids for page content as jQuery Mobile loads multiple div.ui-page content into a single HTML page for performance. I therefore never really understood how I could use id if it might then occur more than once in the HTML body (maybe someone can clarify this).
If I use prop rather than attr the switch goes into an infinite flipping loop! I didn't investigate further...

select all checkboxes command jquery, javascript

I'm trying to get all of my checkboxes to be checked when clicking a link
looks like this: select all
inputs in a loop: <input type="checkbox" name="delete[$i]" value="1" />
jquery code:
var checked_status = this.checked;
$("input[name=delete]").each(function() {
this.checked = checked_status;
});
Can someone help me get it to check all.. ?
When clicking at the select all link, nothing seems to happen.. (not even an error)
Try the following.
Updated. The handler is tied to an anchor therefore there will be no this.checked attribute available.
$("#select_all").click(function(){
$("input[name^=delete]").attr('checked', 'checked');
});
jQuery Tutorial: Select All Checkbox
You're going to want to use the [name^=delete] selector ("starts with"), since your checkboxes names aren't exactly "delete", they're "delete[X]' for some number X.

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