JS: Setting checked to true is not working - javascript

Trying to set a Checkbox via addEventListener in JS, I already tried with
element.checked = true;
element.setAttribute('checked', true);
element.setAttribute('checked', "checked");
I can see in the console that my checked is set to true (not sure if the issue is that the boolean value is shown as string "true" or if this is just a chrome representation) but the element is not getting the check mark.
input id="element" class="element" name="element" type="checkbox"
value="1" checked="true"
Onload the default checked box is correctly set but when I'm trying to uncheck and set the new one nothing is happening (visually).
Thanks for any help.

I'm not sure exactly what you're trying to do but I think you want to toggle one checkbox depending on the state of another.
Have a look at this:
/* get the checkboxes */
const checker1 = document.getElementById('checker');
const checker2 = document.getElementById('checker2');
/* now listen for change on checker1 and action */
/* change the selected state of checker two to be opposite of checker 1 */
checker1.addEventListener('change', () => checker2.checked = !checker1.checked);
<p>
<label for=checker>Click me to toggle the other</label>
<input type=checkbox id=checker>
</p>
<p>
<label>I will be toggled</label>
<input type=checkbox id=checker2 checked>
</p>

So the thing is that if you were supposed to do this manually, Your code would have been like this right:
<input id="element" checked>
In order to achieve the same thing using javascript. It would only happen if you set the checked value to an empty string. Like this:
element.setAttribute("checked","");
This will let your output be like that above.
HOPE IT WORKED OUT FOR YOU :)

Related

django auto check if i save it to database

Here is my html:
<input type="checkbox" value="1" name="Visual" id="visual">
<input type="checkbox" value="1" name="Tuberculosis" id="Tuberculosis">
<input type="checkbox" value="1" name="Skin" id="Skin">
<script type="text/javascript">
$('#checkbox-value').text($('#checkbox1').val());
$("#checkbox1").on('change', function() {
if ($(this).is(':checked')) {
$(this).attr('value', 'true');
} else {
$(this).attr('value', 'false');
}
$('#checkbox-value').text($('#checkbox1').val());
});
</script>
Here is my view:
Visual = request.POST['Visual']
Tuberculosis = request.POST['Tuberculosis']
Skin = request.POST['Skin']
V_insert_data = StudentUserMedicalRecord(
Visual=Visual,
Tuberculosis=Tuberculosis,
Skin=Skin
)
V_insert_data.save(
Why is it every time I save the data to my database, the Visual, Tuberculosis and Skin are automatically checked even though I didn't check it when I was saving it? Or I think my javascript is wrong?
You don't need $('#checkbox-value').text($('#checkbox1').val());, unless you have such element on the page
which you haven't shown us.
You can't define more than one element on the same page with the same id.
(Same goes for the name attribute).
Use different ids as shown in my code and match the chekboxes by class/name.
Don't put value="1" inside your checkboxes.
Put your jQuery code inside a $(function() { }); which is an alias for $( document ).ready().
More info here.
Don't use bare request.POST values, use the sanitized self.cleaned_data['var_name'] instead.
I don't think it's a good idea to have param names with capital letters (this is just a note, it will not impact the functionality). According
to Python's PEP 8, only classes should start with a capital letter.
Frontend:
<input type="checkbox" name="Visual" id="checkbox1" class="checkbox-js-trigger-class">
<input type="checkbox" name="Tuberculosis" id="checkbox2" class="checkbox-js-trigger-class">
<input type="checkbox" name="Skin" id="checkbox3" class="checkbox-js-trigger-class">
<script type="text/javascript">
$(function() {
$(".checkbox-js-trigger-class").on("change", function(){
var new_val = $(this).is(':checked') ? 1 : 0;
$(this).val(new_val);
});
});
</script>
Backend:
It's best to use Model Form:
class StudentUserMedicalRecordForm(ModelForm):
class Meta:
model = StudentUserMedicalRecord
fields = ['Visual', 'Tuberculosis', 'Skin']
Because you have default value given as "1" here
<input type="checkbox" value="1" name="Visual" id="visual">
And also there is no element with id = "checkbox1" or id = "checkbox-value" which are referenced in your script.
Checkbox inputs are actually a little strange and work differently than how you think they work.
You don't need jQuery to handle the case when a checkbox has been changed. The browser and HTML handle that for you. (Sort of like how you don't need to listen for keys being pressed while the user is focused on a input type="text" to make letters show up in the text box.)
Instead, what happens is if the user checks the checkbox, the input will have an attribute called checked. It can look something like this .
The checkbox input tag also has two other attributes name and value. These are what get sent to the server when the form is submitted. BUT it only sends the name and value pair for the checkboxes that are checked! For the checkboxes that are not checked, it sends nothing. So if every checkbox has a name and value you can think of it as a key-value pair. If the check box is checked, it will send key=value to the server. You are allowed to have more than one value for a single key if you designate the name as being the name of an array.
So imagine you have a form like this:
<input type="checkbox" name="disease[]" value="tuberculosis" checked>
<input type="checkbox" name="disease[]" value="chickenpox" checked>
<input type="checkbox" name="disease[]" value="smallpox">
<input type="checkbox" name="needs_medicine" value="true" checked>
<input type="checkbox" name="recovered" value="whatevervalue">
When that form is submitted, the server will receive something that looks like "disease=[tuberculosis,chickenpox]&needs_medicine=true"
Notice that smallpox and recovered are not mentioned because they are not checked. Also notice that it's not super important what you put as the value of a checkbox that is not a multiple choice checkbox (in this example, needs_medicine) because the value that gets sent to the server will always either be the value of the checkbox (in this case, the string "true").

JQuery: Getting a series of checkboxes to validate

I'm trying to get a group of checkboxes as part of an overall form I created in the admin area of WordPress to validate. Basically, custom fields. Here's what the code looks like:
<div><label><input type="checkbox" value="0-2" name="_ecp_custom_5[]" /> 0-2</label></div>
<div><label><input type="checkbox" value="3-5" name="_ecp_custom_5[]" /> 3-5</label></div>
<div><label><input type="checkbox" value="6-8" name="_ecp_custom_5[]" /> 6-8</label></div>
and so on.....
So I have this in my JavaScript:
jQuery(document).ready(function($) {
$('[name="_ecp_custom_3"]').attr("required", true);
$('[name="_ecp_custom_5[]"]').prop("checked", true);
});
First line for a text field, works great. But the checked one underneath doesn't work at all. If I submit the form without checking a box, the form still publishes and when it comes back, all the fields are now checked even though I didn't check any of them.
Puzzled what to do in regards to that since there's going to be several rules in this validation function.
If you are using html:
An html element name and id cannot include special characters, such as [ ], and must begin with a letter (A-Z), (a-z).
Aside from that, your jQuery references an element with the name=_ecp_custom_5 and not name=_ecp_custom_5[]. Simply remove the [] in your names and your code will work.
Update
The $('[name=foo]').prop("checked", true) sets all checkboxes with name=foo to checked. I'm a bit confused about what you are asking at this point, since it seems like you are confused about why your form is submitting all checkbox inputs as checked?
You want to require that at least one checkbox is checked, right?
You can iterate all inputs with the name attribute value of "_ecp_custom_5[]" by using jQuery.each(). With that, you can create any flag variable that will be used on any condition.
Please refer to the snippet below if you can't visualize what I am trying to say.
If you want to require that at least one checkbox is checked, you can use this example as your basis
$(function() {
$('#btnValidate').click(function() {
var flag = false;
$.each($('[name="_ecp_custom_5[]"]'), function(index, value) {
var checkboxStatus = $(this).prop('checked');
if (checkboxStatus == true) {
flag = checkboxStatus;
}
});
if (flag == false) {
alert('No checkbox has been checked')
} else {
alert('Success!')
}
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div>
<label>
<input type="checkbox" value="0-2" name="_ecp_custom_5[]" /> 0-2
</label>
</div>
<div>
<label>
<input type="checkbox" value="3-5" name="_ecp_custom_5[]" /> 3-5
</label>
</div>
<div>
<label>
<input type="checkbox" value="6-8" name="_ecp_custom_5[]" /> 6-8
</label>
</div>
<button id="btnValidate" style="margin-top: 20px;">Validate</button>
How I did it?
I iterated all inputs with the name attribute value of "_ecp_custom_5[]".
Then I created a boolean variable named "flag" (default value is false) that is being changed to true only if a checkbox from the iteration has the prop('checked') value of true. If no checkbox has been checked, then the "flag" variable's value will remain false which will then be checked by my condition.

Checkbox always On

Why this code always alert "on"? No matter if it's checked or unchecked, it always print on.
click:
<input type="checkbox" onclick="alert(this.value)" />
http://jsfiddle.net/5yn78jhz/
Use "this.checked" instead of "value" to get true or false for checked or unchecked.
Your checkbox doesn't have a value, so JavaScript uses the default value. If you want something else, you'll need to use the value attribute value="some value". Also, the code isn't checking to see if the checkbox has been checked or not, so it will always give you the value of the checkbox, whether it's checked or not.
For example
<input type="checkbox" onclick="if(this.checked) { alert(this.value); }" />
Will only display something if the checkbox is checked.
This is the way onclick action works. You can use a js function to check if is true/false like this:
html
<input type="checkbox" onclick="check(this)" />
js
function check(obj){
if(obj.checked){
alert(obj.value);
}
}
fiddle

How change event work on radio buttons

the change function catch only if radio is checked but not when its unchecked. Why? Should it behave like that? When I click the radio button the other is unchanging so the event should fire, right? Below is the code and jsfiddle. Do I do anything wrong?
HTML:
Option1 <input type="radio" name="choice" id="op1" checked/>
Option2 <input type="radio" name="choice" id="op2"/>
<br><br>
<span id="sp1">Option1</span><br>
<span id="sp2" style="display: none;">Option2</span>
Javascript:
var op2 = $('#op2');
var sp1 = $('#sp1');
var sp2 = $('#sp2');
op2.change(function(){
if(op2.is(':checked')){
sp1.hide();
sp2.show();
}
else{
sp2.hide();
sp1.show();
}
});
You can run your event handler when either checkbox changes:
$('#op2, #op1').change(...
Here's a demo: http://jsfiddle.net/TCt82/
Another way to select this would be by element name since both checkboxes need to have the same name attribute. Selecting by ID will be faster (although you won't be able to see the difference).
UPADTE
If anyone knows the exact reason the change event does not fire on a checkbox after it's been de-selected, posting it as a comment or answer would be great.
Change your selector to get it using the name
$("input[name='choice']").change(function(){
if(op2.is(':checked')){
sp1.hide();
sp2.show();
}
else{
sp2.hide();
sp1.show();
}
});
Working sample http://jsbin.com/UPILuCe/1

Grouped radiobuttons check changed

I am currently working on a project where we render a dynamic page based on what we are holidng in a SQL table. We have conditional validation for controls where you can say
if x is equal to y then enable controls abc
I have multiple radio buttons in a group, the last control is "Other (please specify)" which when true will enable a textbox to specify so I need to capture when this is set to both true or false. Currently I am doing something like this
<input type="radio" name="test" value="Yes" />
<input type="radio" onchange="onChange()" name="test" value="No" />
<script type="text/javascript">
function onChange() {
alert('Changed')
}
</script>
If I check NO I get an alert. If I then check YES it changes the NO radio button checkstate but doesn't display an alert - any solutions?
The only thing I can suggest is putting an onchange on the whole group and then checking which is selected when they change. Not very elegant but it appears that this is just how the change event works (ie it only responds to a user change, not to a system change of it).

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