Rules, allow you to change the formats (text color, background color, style) and visibility of a control depending upon a condition.
Rule Condition
This is the condition, that the formattings will apply when it's true.
return $Xml.EvaluateBoolean('Score > 10');
For this example, all formatting styles will apply when "Score" value is greater than 10.
Hidden
If chosen Yes, it will make control invisible. (when rule condition is true)
Disabled
If chosen Yes, it will make control readonly. (when rule condition is true)
Bold
If chosen, it will make the text bold. (when rule condition is true)
Italic
If chosen, it will make the text italic. (when rule condition is true)
TextColor
Sets the color of the text that will be seen when rule condition is true.
Background Color
Sets the background color of the text that will be seen when rule condition is true.