Checkbutton: what are the jscallback() arguments?

Panel
#1

How would I figure out the arguments of the jscallback function for some panel widgets?
I have a pn.widgets.CheckBox, and want to set some javascript to execute when
the checkbox is set/unset.

All I can figure out is that i need cb.jscallback( args={}, ??? )

#2

got a little further: this triggers

cb = pn.widgets.Checkbox(name="Show Left Bottom Corner")
cb.jscallback(**{"value": "console.log('value changed');"} )
cb

now how do I get at the value in javascript?

#3

Still struggling with this…

cb = pn.widgets.Checkbox(name="Show Left Bottom Corner")
display(cb)

def cb_proc(event):
    Javascript('console.log( "got an event...")')
    print("Checked:", event.new)
cb.param.watch(cb_proc, "value" )

Clicking on the checkbox prints Checked True in the notebook, and

Python callback returned following output: 
	Checked: True

in the console: it does not appear to execute the Javascript.

@philippjfr how do I get the checkbox value in javascript, please?
I just can’t figure it out?

#4

Sorry, missed this. For all jscallbacks there is always a cb_obj in the arguments, which in this case represents the widget model. The Checkbox is actually a reduced case of a checkbox group so it has an active property, which represents the checked items and since there’s only one item active is either empty ([]) or contains a zero-index ([0]).

A callback that reports true or false therefore would look like this:

cb.jscallback(**{"value": "console.log(cb_obj.active.length ? true : false);"} )
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