html5 - data-bind="attr:{for:id()+'check'}" do not work for 2.3 android but work for 4.0+ android -

i using phonegap, html 5,knockout develop
below code not work 2.3 android work 4.0+ android

<input type="checkbox" data-bind="checked: ischecked,attr:{id:id()+'check'}" class="checkboxinput" />                 <label data-bind="attr:{for:id()+'check'}"></label> 

may script error none of knockout data load after that.

where code below (hard-coded without ko) works

<input type="checkbox" id="test" class="checkboxinput" />                 <label for="test"></label> 

thanks attention edward van raak

just small change, single quotes? 'for':id() , work

<label data-bind="attr:{'for':id()+'check'}"></label>