CODEWITHSUNDEEP
javascriptknockout.js
Matt Holmes
Matt Holmes

Reputation: 1065

KnockoutJS: Using 'html' binding, new elements not binding

I have a view model which contains a ko.observable representing the conent of a div, like so:

function claimContainerViewModel(elem, api) {
    this.content = ko.observable('<somecontent>');
}

At some later time, I update that content using an AJAX call, and I have a div with the following binding:

<div id="ClaimContainer" data-bind="html: content">

The HTML returned for 'content' has data-bind's of it's own, and this is the issue: None of those bindings are being parsed. According to Knockout, and every source I've read, this is supposed to happen. When using the 'html' binding, KO is supposed to be smart enough to do a re-bind.

Is this a bug in KO 2.2.0 (the version I am stuck with right this very second), or am I misinterpreting how the html binding handler works? And before anyone asks, no applyBindings will not work in this case, because the container uses an html bind, which applyBindings assumes is supposed to handle the re-bind itself (I've confirmed this by stepping down in to KO's code).

Upvotes: 12

Views: 2643

Answers (1)

Matt Holmes
Matt Holmes

Reputation: 1065

UPDATE:

This is the final version of my custom binding. This now works automatically, doesn't doubly bind, and works just like the 'html' binding, but more dynamic.

if (!ko.bindingHandlers['dynhtml']) {
    ko.bindingHandlers['dynhtml'] = {
        'init': function() {
            return { 'controlsDescendantBindings': true };
        },
        'update': function (element, valueAccessor, allBindings, viewModel, bindingContext) {
            ko.utils.setHtml(element, valueAccessor());
            ko.applyBindingsToDescendants(bindingContext, element);
        }
    };
}

Please, please, PLEASE be aware that this can be unsafe if you don't know the source of your HTML. Very, very unsafe. If unsanitized user input can ever make it in to your HTML, this could be a huge security hole, so watch out for cross site scripting attacks.

Upvotes: 19

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