====== Boolean Variables ======

A boolean variable can only be two values : ''true'' or ''false''. Generally, such a variable is associated  with a Checkbox field. It can be used with boolean properties inside the canvas, such as the ''visible'' one.

To use a **Boolean Variable**, use the text ''?myVariable'', with the name corresponding to the field defined.

<code javascript>
"canvasFields": [
    {"type":"rect", "visible": "?isDisplayed", "width": 330, "height":40, "left":5, "top":450, "fill":"#B1E29E", "stroke":"#000000"},
]
</code>

==== Not value ====

What if you need to get the inverse result of the checkbox ? Then, you can add the code ''?!isNot'' to get the inverse result. If your checkbox ''isNot'' is checked, it will return ''false''.