# Conditional Expressions

Conditional Expressions return False or True (0 or 1). These Expressions are usually used in the “If” and “While” Actions. 

When editing an Expression of this type, you have available [Functions ](https://doc.sysdevmobile.com/kalipso5/developing/form/expressions/functions)and all the Kalipso objects from where you can retrieve values ([Global Variables](https://doc.sysdevmobile.com/kalipso5/developing/form/variables), [Controls ](https://doc.sysdevmobile.com/kalipso5/developing/form/controls)and [Local Variables](https://doc.sysdevmobile.com/kalipso5/developing/form/option-window/local-variables)). To use any of these items you just have to double-click it and it will be automatically added to the Expression.

### Examples:

* *Example 1*

CTRL(iProduct) = ""

* *Example 2*

CTRL(iProduct) = "" and CTRL(iStock) > 0