Non-boolean attributes (per the HTML5 spec) are incorrectly removed by the attr binding when given boolean values

[bramstein]

When I use the attr binding to set the draggable (non-boolean) attribute it is removed completely from the DOM when the expression evaluates to false. This is incorrect as img and a elements are draggable by default, so it is impossible to set them to be not draggable using Knockout. I had a quick look at the attr binding code and it seems to always remove an attribute when its expression evaluates to false. This should only happen when the attribute is actually a boolean attribute. The following are all boolean attributes from the HTML5 spec grouped by the elements they are legal on:

• all elements: hidden
• script: async, defer
• button: autofocus, formnovalidate, disabled
• input: autofocus, formnovalidate, multiple, readonly, required, disabled, checked
• keygen: autofocus, disabled
• select: autofocus, multiple, required, disabled
• textarea: autofocus, readonly, required, disabled
• style: scoped
• ol: reversed
• command: disabled, checked
• fieldset: disabled
• optgroup: disabled
• option: selected, disabled
• audio: autoplay, controls, loop, muted
• video: autoplay, controls, loop, muted
• iframe: seamless
• track: default
• img: ismap
• form: novalidate
• details: open
• object: typemustmatch
• marquee: truespeed

Is is possible for Knockout to only remove attributes when the attr binding expression evaluates to false and the attribute is an actual boolean attribute?

[mbest]

Can you use data-bind="attr: { draggable: 'false' }"?

[mbest]

Closing, as this is something we're not likely to include in Knockout.