Small fully-customisable checkbox/radiobutton widget.
new Checkbox(elem, options)
Checkbox(elem, options)
[new] Checkbox([elem0, elem1, ...], options)
[new] Checkbox(nodeList, options)
There are 3 parameters, that can be passed to constructor:
"template" - template for single checkbox/radiobutton (default: '<div class="checkbox">[text]</div>')
"class-checked" - className for widget, showing checked checkbox
"attr-text" - name of the checkbox's attribute, that containes [text] value for the template