xCheckBox  L T W H Title Variable OnText OffText ON|OFF

Specifies a checkbox type gadget at Left, Top, sized Width Height.
The Title will be placed next to the gadget.
Variable is the name of the variable that will hold the value.

Checkbox type gadgets have two states : Checked (ON) & Unchecked (OFF)
If the gadget is ON, OnText will be placed in Variable, otherwise,
OffText.
ON|OFF specify the starting state of the gadget, when the window first
opens.

Example :

xCheckBox  30 15 16 16 "CheckBox" ChkVar "Yes" "No" OFF

Here, if the user checks the gadget, then the variable ChkVar
will contain the word "Yes"

Example gui :  Run Gui   Source