December 2014
Intermediate to advanced
102 pages
1h 45m
English
Content preview from Knockout.js
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Chapter 5. Working with Forms
Form Data Bindings
Knockout provides several different bindings that work with specific form elements.
- The
valuebinding is used withinput,select, andtextareaform inputs. - The
textInputbinding is also used withinputandtextareaand is quite similar to thevaluebinding. When thetextInputis used, the observable updates with every user interaction, as opposed to thevaluebinding, which defaults to updating when the form element changes (typically when the field loses focus). See Example 5-1. - The
checkedbinding is used with checkboxes and radio buttons. - The
optionsbinding is used on theselectform input to populate the list of options available in the drop-down list. - The
selectedOptionsbinding is also used with theselectform input; more specifically when you are using a multiselect list. This is commonly bound to an observable array, as opposed to an observable variable. - The
enableanddisablebindings work with all form inputs to either enable or disable the form element when the condition results to true or false, respectively.
All of these bindings are what Knockout calls two-way bindings. This means that when the form element is changed, your ViewModel property is updated and if you programmatically change the observable, the form element it is binded to will be automatically updated.
Example 5-1. The textInput binding
<!DOCTYPE html><html><head><title>Data Binding with KnockoutJS</title></head><body><textareadata-bind= ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.