I'm building a *ngFor dynamic radio button. I need to add some kind of attribute that can be used to determine if the button is active or not. This is not for the purpose of functionality, the selection builds the property on my reactive form fine. The purpose is to satisfy testing.
<label *ngFor="let order of orders">
<input formControlName="orders" type="radio" name="orders" [value]="order.id" />
{{order.name}}
</label>
I've tried adding a checked attribute but this just adds the attribute to all radios. I thought angular provided a ngChecked property, but I think that was for AngularJS.
Any solution to determine/show that the selected radio is active would be a solution.
https://stackblitz.com/edit/angular-t2gd4g
simply by get the value of the form control orders you will be applied to know the selected one or in case of apply a spesifect design you can add a checked class for the selected one
<label *ngFor="let order of orders"
[ngClass]="{'checked':form.get('orders').value == order.id}">
<input formControlName="orders" type="radio" name="orders" [value]="order.id" />
{{order.name}}
</label>
another way to get the selected order by create a property
get selectedOrder() {
const selected =this.form.get('orders').value;
if (selected) {
return this.orders.find(o => o.id == selected )
} else {
return null
}
}
demo 🚀
In your .ts file declare changeHandler() function like this :
changeHandler(index){
console.log(`radio-button ${index+1} is active`);
}
In your .html file, in your *ngFor declare index which can be used to find the current state of checkbox. So the following demo shows which checkbox is active :
<label *ngFor="let order of orders; let i = index;">
<input formControlName="orders" type="radio" name="orders" [value]="order.id" (ngModelChange)="changeHandler(i)"/>
{{order.name}}
</label>
Demo : enter link description here
Note : see console to see active button
<input type="text" class="form-control"
id="transactionAmount"
maxlength="10"
OnlyNumber="true"
[(ngModel)]="userBalance.transactionAmount"
name="transactionAmount"
placeholder="Amount"
required
#transactionAmount="ngModel">
Here I have to hide zero amount while user entering the values.
If he enters all zero's then only we have to hide not in cases like 20,30,100 etc...
I'm using Angular 2.
<input type="text" class="form-control"
id="transactionAmount"
maxlength="10"
OnlyNumber="true"
[(ngModel)]="userBalance.transactionAmount"
name="transactionAmount"
placeholder="Amount"
required
#transactionAmount="ngModel"
(keyup)="hideZero()>
Added This keyUp event in Html and in .ts added below code
hideZero(){
if(this.userBalance.transactionAmount === '0' ){
this.userBalance.transactionAmount = '';
}
}
Working Absolutely fine
/* In your ts */
validateNumber(value: String) {
userBalance.transactionAmount = value && value.replace(/(?:0*)(\d*)/g, (_,value1) => {
return value1;
})
}
<input (input)="validateNumber($event)">
Try using (ngModelChange) event which will trigger when user types values. By using regex, you can remove the last zero value and update the DOM. Hope this helps.
Angular 0 value don't display
<span *ngIf="!pro.model === '0'">{{ pro.model }}</span>
Like this,
When model value is zero that time don't display model value.
If model value is not zero that time show model value in your html pages.
Is it possible to have a single checkbox with two values ? i have a checkbox called "full-day ?".
<div class="input-field col s2">
<p>
<input type="checkbox" id="test6" value="yes" ng-model="isFull"/>
<label for="test6">Half Day</label>
</p>
</div>
if the user checks it a yes should be passed when i press submit button and if the checkbox is not checked a no have to be passed.As far as i know if the checkbox is not activated html treats as if checkbox is not present and it wont be included in the query string.Here using radio button is not an option.Please let me know how do i go about it.
This is simple:
<input type="hidden" id="test6" value="no" ng-model="isFull" checked>
<input type="checkbox" id="test6" value="yes" ng-model="isFull">
<label for="test6">Half Day</label>
It is boolean.
Code is processed sequentially
Only the last 'checked' answer is used.
Therefore put the 'non' answer first but hide it and leave it always checked. The positive answer comes second.
If the form is editable (user can come back and change their answer) code to check the single visible checkbox appropriately e.g.
<?php if ($fieldValue=='Yes' ){ echo 'checked'; } ?>
Works for me!
Not really.
You can fake things with JavaScript that injects hidden inputs, but this is better handled with server side code.
e.g.
my $value;
if ($request->param("checkbox_name") {
$value = "yes";
} else {
$value = "no";
}
In AngularJS; How do I toggle between two checkboxes and get only one value
<td >
<input type="checkbox" value="{{person.person_ID}}">{{person.home_address}}
</td>
<td >
<input type="checkbox" value="{{person.person_ID}}">{{person.office_address}}
</td>
According to the requirement I have list of persons in that every person has two
columns home_address and office_address, I want to toggle between addresses and get only 1
value like if person.home_address is checked than office_address should be unchecked and vice versa, and I want to get only 1 address like "person.person_ID":home_address
You can use ng-model to bind to a value in your person instance using the following html. (A fiddle is available)
<input type="checkbox"
ng-model="person.option"
value="{{person.person_ID}}"
ng-true-value="'home'"
ng-false-value="'none'">{{person.home_address}}
<input type="checkbox"
ng-model="person.option"
value="{{person.person_ID}}"
ng-true-value="'office'"
ng-false-value="'none'">{{person.office_address}}
here the checkboxes binds to the same variable person.option which is set depending on the value of the checkbox to the expression in ng-true-value and ng-false-value. By setting these to the some value other than that of the other we can either select none, or only one.
In your controller you can simply check person.option to get what checkbox is selected.
if (person.option === 'home') { }
else if (person.option === 'office') { }
Is it standard behaviour for browsers to only send the checkbox input value data if it is checked upon form submission?
And if no value data is supplied, is the default value always "on"?
Assuming the above is correct, is this consistent behaviour across all browsers?
Yes, standard behaviour is the value is only sent if the checkbox is checked. This typically means you need to have a way of remembering what checkboxes you are expecting on the server side since not all the data comes back from the form.
The default value is always "on", this should be consistent across browsers.
This is covered in the W3C HTML 4 recommendation:
Checkboxes (and radio buttons) are on/off switches that may be toggled
by the user. A switch is "on" when the control element's checked
attribute is set. When a form is submitted, only "on" checkbox
controls can become successful.
In HTML, each <input /> element is associated with a single (but not unique) name and value pair. This pair is sent in the subsequent request (in this case, a POST request body) only if the <input /> is "successful".
So if you have these inputs in your <form> DOM:
<input type="text" name="one" value="foo" />
<input type="text" name="two" value="bar" disabled="disabled" />
<input type="text" name="three" value="first" />
<input type="text" name="three" value="second" />
<input type="checkbox" name="four" value="baz" />
<input type="checkbox" name="five" value="baz" checked="checked" />
<input type="checkbox" name="six" value="qux" checked="checked" disabled="disabled" />
<input type="checkbox" name="" value="seven" checked="checked" />
<input type="radio" name="eight" value="corge" />
<input type="radio" name="eight" value="grault" checked="checked" />
<input type="radio" name="eight" value="garply" />
Will generate these name+value pairs which will be submitted to the server:
one=foo
three=first
three=second
five=baz
eight=grault
Notice that:
two and six were excluded because they had the disabled attribute set.
three was sent twice because it had two valid inputs with the same name.
four was not sent because it is a checkbox that was not checked
six was not sent despite being checked because the disabled attribute has a higher precedence.
seven does not have a name="" attribute sent, so it is not submitted.
With respect to your question: you can see that a checkbox that is not checked will therefore not have its name+value pair sent to the server - but other inputs that share the same name will be sent with it.
Frameworks like ASP.NET MVC work around this by (surreptitiously) pairing every checkbox input with a hidden input in the rendered HTML, like so:
#Html.CheckBoxFor( m => m.SomeBooleanProperty )
Renders:
<input type="checkbox" name="SomeBooleanProperty" value="true" />
<input type="hidden" name="SomeBooleanProperty" value="false" />
If the user does not check the checkbox, then the following will be sent to the server:
SomeBooleanProperty=false
If the user does check the checkbox, then both will be sent:
SomeBooleanProperty=true
SomeBooleanProperty=false
But the server will ignore the =false version because it sees the =true version, and so if it does not see =true it can determine that the checkbox was rendered and that the user did not check it - as opposed to the SomeBooleanProperty inputs not being rendered at all.
If checkbox isn't checked then it doesn't contribute to the data sent on form submission.
HTML5 section 4.10.22.4 Constructing the form data set describes the way form data is constructed:
If any of the following conditions are met, then skip these substeps
for this element:
[...]
The field element is an input element whose type
attribute is in the Checkbox state and whose checkedness is false.
and then the default valued on is specified if value is missing:
Otherwise, if the field element is an input element whose type attribute is in the Checkbox state or the Radio Button state, then run these further nested substeps:
If the field element has a value attribute specified, then let value be the value of that attribute; otherwise, let value be the string "on".
Thus unchecked checkboxes are skipped during form data construction.
Similar behavior is required under HTML4. It's reasonable to expect this behavior from all compliant browsers.
Checkboxes are posting value 'on' if and only if the checkbox is checked. Insted of catching checkbox value you can use hidden inputs
JS:
var chk = $('input[type="checkbox"]');
chk.each(function(){
var v = $(this).attr('checked') == 'checked'?1:0;
$(this).after('<input type="hidden" name="'+$(this).attr('rel')+'" value="'+v+'" />');
});
chk.change(function(){
var v = $(this).is(':checked')?1:0;
$(this).next('input[type="hidden"]').val(v);
});
HTML:
<label>Active</label><input rel="active" type="checkbox" />
Is it standard behaviour for browsers to only send the checkbox input
value data if it is checked upon form submission?
Yes, because otherwise there'd be no solid way of determining if the checkbox was actually checked or not (if it changed the value, the case may exist when your desired value if it were checked would be the same as the one that it was swapped to).
And if no value data is supplied, is the default value always "on"?
Other answers confirm that "on" is the default. However, if you are not interested in the value, just use:
if (isset($_POST['the_checkbox'])){
// name="the_checkbox" is checked
}
None of the above answers satisfied me.
I found the best solution is to include a hidden input before each checkbox input with the same name.
<input type="hidden" name="foo[]" value="off"/>
<input type="checkbox" name="foo[]"/>
Then on the server side, using a little algorithm you can get something more like HTML should provide.
function checkboxHack(array $checkbox_input): array
{
$foo = [];
foreach($checkbox_input as $value) {
if($value === 'on') {
array_pop($foo);
}
$foo[] = $value;
}
return $foo;
}
This will be the raw input
array (
0 => 'off',
1 => 'on',
2 => 'off',
3 => 'off',
4 => 'on',
5 => 'off',
6 => 'on',
),
And the function will return
array (
0 => 'on',
1 => 'off',
2 => 'on',
3 => 'on',
)
input type="hidden" name="is_main" value="0"
input type="checkbox" name="is_main" value="1"
so you can control like this as I did in the application.
if it checks then send value 1 otherwise 0
From HTML 4 spec, which should be consistent across almost all browsers:
http://www.w3.org/TR/html401/interact/forms.html#checkbox
Checkboxes (and radio buttons) are on/off switches that may be toggled
by the user. A switch is "on" when the control element's checked
attribute is set. When a form is submitted, only "on" checkbox
controls can become successful.
Successful is defined as follows:
A successful control is "valid" for submission. Every successful
control has its control name paired with its current value as part of
the submitted form data set. A successful control must be defined
within a FORM element and must have a control name.
I have a page (form) that dynamically generates checkbox so these answers have been a great help. My solution is very similar to many here but I can't help thinking it is easier to implement.
First I put a hidden input box in line with my checkbox , i.e.
<td><input class = "chkhide" type="hidden" name="delete_milestone[]" value="off"/><input type="checkbox" name="delete_milestone[]" class="chk_milestone" ></td>
Now if all the checkboxes are un-selected then values returned by the hidden field will all be off.
For example, here with five dynamically inserted checkboxes, the form POSTS the following values:
'delete_milestone' =>
array (size=7)
0 => string 'off' (length=3)
1 => string 'off' (length=3)
2 => string 'off' (length=3)
3 => string 'on' (length=2)
4 => string 'off' (length=3)
5 => string 'on' (length=2)
6 => string 'off' (length=3)
This shows that only the 3rd and 4th checkboxes are on or checked.
In essence the dummy or hidden input field just indicates that everything is off unless there is an "on" below the off index, which then gives you the index you need without a single line of client side code.
.
Just like ASP.NET variant, except put the hidden input with the same name before the actual checkbox (of the same name). Only last values will be sent. This way if a box is checked then its name and value "on" is sent, whereas if it's unchecked then the name of the corresponding hidden input and whatever value you might like to give it will be sent. In the end you will get the $_POST array to read, with all checked and unchecked elements in it, "on" and "false" values, no duplicate keys. Easy to process in PHP.
Having the same problem with unchecked checkboxes that will not be send on forms submit, I came out with a another solution than mirror the checkbox items.
Getting all unchecked checkboxes with
var checkboxQueryString;
$form.find ("input[type=\"checkbox\"]:not( \":checked\")" ).each(function( i, e ) {
checkboxQueryString += "&" + $( e ).attr( "name" ) + "=N"
});
in your post
'your_field': your_field.is(':checked'),
I resolved the problem with this code:
HTML Form
<input type="checkbox" id="is-business" name="is-business" value="off" onclick="changeValueCheckbox(this)" >
<label for="is-business">Soy empresa</label>
and the javascript function by change the checkbox value form:
//change value of checkbox element
function changeValueCheckbox(element){
if(element.checked){
element.value='on';
}else{
element.value='off';
}
}
and the server checked if the data post is "on" or "off". I used playframework java
final Map<String, String[]> data = request().body().asFormUrlEncoded();
if (data.get("is-business")[0].equals('on')) {
login.setType(new MasterValue(Login.BUSINESS_TYPE));
} else {
login.setType(new MasterValue(Login.USER_TYPE));
}