Template Syntax
If-Else

An if-else structure looks like this:

<if condition>
    Some HTML...
</if>

Or like this:

<if condition>
    Some HTML...
<else>
    Some other HTML...
</if>

The condition should be a boolean expression. For example:

<if !(color == "blue" || color == "violet")>
    You have an unusual favorite color.
</if>

<if foo && (!(bar || baz) || elephant)>
    Tweedledee.
</if>

Since undefined, null, and empty values evaluate to false, it is convenient to use idioms like the following:

<if error>
    <p>Your request cannot be processed because of the following error:<br>
    ${error}
<else>
    (display results...)
</if>

Since undefined, null, and empty values are considered equal, the following two statements are equivalent, whether foo is defined or not:

<if foo> ... </if>

<if foo != ""> ... </if>