CODEWITHSUNDEEP
knockout.js
dreamerkumar
dreamerkumar

Reputation: 1550

knockout binding how to remove an attribute

Let's say I have an Html element

<element testattribute='a'></element>

I know I can pass the value of testattribute using a binding like this:

<element data-bind="attr: { testattribute: 'a'}></element>

But how can I completely remove this attribute through the binding. So if the original value was 

 <element testattribute: 'a'></element>

my end result should be 

<element></element>

Upvotes: 15

Views: 4386

Answers (3)

john Smith
john Smith

Reputation: 17926

you should do this ternary inline because form not accepts several checked radio button and it will ignore the knockout comments so none would be checked to avoid do like:

<input type="radio" data-bind="attr:{'checked':($data.amount > 0) ? 'checked' : false}" id="q156" name="foo" value="positive" />

this will set accurate!

Upvotes: 3

RP Niemeyer
RP Niemeyer

Reputation: 114792

The attr binding in KO will actually remove the attribute if the value is false, null, or undefined. So, if you bind against an observable and then set it to one of those values (not empty string), then the attribute will be removed.

Upvotes: 28

Smeegs
Smeegs

Reputation: 9224

You can use conditional binding to show the element

http://knockoutjs.com/documentation/if-binding.html

What you could do, is have two versions of the element, one with the attr binding, and one without, and use the following code to figure out what should be displayed for that particular binding.

<!-- ko if: someExpressionGoesHere -->
        <element data-bind="attr: { testattribute: 'a'}></element>
<!-- /ko -->
<!-- ko if: someExpressionGoesHere == false -->
        <element></element>
<!-- /ko -->

Upvotes: 0

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