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If / Else#

In all programming languages, comparisons form the basis for flow control. Conditional statements are used to perform different actions based on different conditions.

Conditional Statements#

MivaScript provides the following conditional statements:

  • MvIF expression: execute some code only if a specified condition is true.
  • MvIF…MvELSE statement: execute one block of code if the condition is true and another block if it is false.
  • MvIF…MvELSEIF…MvELSE statement: select one of many blocks of code to be executed.

Attributes#

  • EXPR: Required. Returns a value interpreted as a conditional expression, typically involving a comparison, string, or logic operator. The expression must evaluate to true for MivaScript to process the code that follows the <MvIF> tag. An <MvIF> tag must have a closing </MvIF> end tag.

Syntax#

<MvIF EXPR="{ condition }">
    Execute the code here if this condition is true, otherwise skip it.
</MvIF>

Examples#

Basic If…Else#

<MvIF EXPR="{ s.tm_hour LT 12 }">
    Good Morning.<br>
<MvELSE>
    Good Afternoon.<br>
</MvIF>

In this example, the code executed branches based on the system clock’s current hour of the day, where LT means Less Than. See Operators.

If…ElseIf…Else#

<MvIF EXPR="{ g.month LE 3 }">
    First Quarter.<br>

<MvELSEIF EXPR="{ g.month LE 6 }">
    Second Quarter.<br>

<MvELSEIF EXPR="{ g.month LE 9 }">
    Third Quarter.<br>

<MvELSE>
    Fourth Quarter.<br>
</MvIF>

Multiple conditions can be used to determine which of several blocks of code to execute.

Nested Conditionals#

You can nest <MvIF> tags—enclose one inside another. Each <MvIF> tag must have a corresponding </MvIF> end-tag. Indenting nested tags is not required but makes your code more readable.

<MvIF EXPR="{ age GE 17 }">
    This person may be eligible to drive a motor vehicle.<br>
    <MvIF EXPR="{ age GT 80 }">
        This person requires a re-examination.<br>
    </MvIF>
    The license fee is $40.75.<br>
</MvIF>