If

A conditional block that is evaluated if the attributes/modifiers evaluate true. This tag can be used in combination with the ElseIf and Else tags to test for a variety of cases.

The opposite — that is, to evaluate if false — is <mt:Unless>.

Attributes

• name

• var: Declares a variable to test. When none of the comparison attributes are present (“eq”, “ne”, “lt”, etc.) If tag tests if the variable has a “true” value, meaning if it is assigned a non-empty, non-zero value.

• tag: Declares a MT tag to execute; the value of which is used for testing. When none of the comparison attributes are present (“eq”, “ne”, “lt”, etc.) the If tag tests if the specified tag produces a “true” value, meaning if it produces a non-empty, non-zero value. For MT conditional tags, the If tag passes through the logical result of that conditional tag.

• op: If specified, applies the specified mathematical operator to the value being tested. op may be one of the following (those that require a second value use the value attribute):

* + or add: addition * - or sub: subtraction * ++ or inc: adds 1 to the given value * -- or dec: subtracts 1 from the given value * * or mul: multiplication * / or div: division ** % or mod: issues a modulus operator

• value: Used in conjunction with the op attribute.

• eq: Tests whether the given value is equal to the value of the eq attribute.

• ne: Tests whether the given value is not equal to the value of the ne attribute.

• gt: Tests whether the given value is greater than the value of the gt attribute.

• lt: Tests whether the given value is less than the value of the lt attribute.

• ge: Tests whether the given value is greater than or equal to the value of the ge attribute.

• le: Tests whether the given value is less than or equal to the value of the le attribute.

• like: Tests whether the given value matches the regex pattern in the like attribute.

• test: Uses a Perl (or PHP under Dynamic Publishing) expression. For Perl, this requires the “Safe” Perl module to be installed.

Examples

If variable “foo” has a non-zero value:

    <mt:SetVar name="foo" value="bar">
    <mt:If name="foo">
        <!-- do something -->
    </mt:If>

If variable “foo” has a value equal to “bar”:

    <mt:SetVar name="foo" value="bar">
    <mt:If name="foo" eq="bar">
        <!-- do something -->
    </mt:If>

If variable “foo” has a value that starts with “bar” or “baz”:

    <mt:SetVar name="foo" value="barcamp" />
    <mt:If name="foo" like="^(bar|baz)">
        <!-- do something -->
    </mt:If>

If tag <$mt:EntryTitle$> has a value of “hello world”:

    <mt:If tag="EntryTitle" eq="hello world">
        <!-- do something -->
    </mt:If>

If tag <$mt:CategoryCount$> is greater than 10 add “(Popular)” after Category Label:

    <mt:Categories>
        <$mt:CategoryLabel$>
        <mt:If tag="CategoryCount" gt="10">(Popular)</mt:If>
    </mt:Categories>

If tag <$mt:EntryAuthor$> is “Melody” or “melody” and last name is “Nelson” or “nelson” then do something:

    <mt:Authors>
        <mt:If tag="EntryAuthor" like="/(M|m)elody (N|n)elson/"
            <!-- do something -->
        </mt:If>
    </mt:Authors>

If the <$mt:CommenterEmail$> matches foo@domain.com or bar@domain.com:

    <mt:If tag="CommenterEmail" like="(foo@domain.com|bar@domain.com)">
        <!-- do something -->
    </mt:If>

If the <$mt:CommenterUsername$> matches the username of someone on the Movable Type team:

    <mt:If tag="CommenterUsername" like="(beau|byrne|brad|jim|mark|fumiaki|yuji|djchall)">
        <!-- do something -->
    </mt:If>

If <$mt:EntryCategory$> is “Comic” then use the Comic template module otherwise use the default:

    <mt:If tag="EntryCategory" eq="Comic">
        <$mt:Include module="Comic Entry Detail"$>
    <mt:Else>
        <$mt:Include module="Entry Detail"$>
    </mt:If>

If <$mt:EntryCategory$> is “Comic”, “Sports”, or “News” then link to the category archive:

    <mt:If tag="EntryCategory" like="(Comic|Sports|News)">
        <a href="<$mt:CategoryArchiveLink$>"><$mt:CategoryLabel$></a>
    <mt:Else>
        <$mt:CategoryLabel$>
    </mt:If>

List all categories and link to categories it the category has one or more entries:

    <mt:Categories show_empty="1">
        <mt:If name="__first__">
    <ul>
        </mt:If>
        <mt:If tag="CategoryCount" gte="1">
        <li><a href="<$MTCategoryArchiveLink$>"><$MTCategoryLabel$></a></li>
        <mt:Else>
        <li><$MTCategoryLabel$></li>
        </mt:If>
        <mt:If name="__last__">
    </ul>
        </mt:If>
    </mt:Categories>

Test a variable using Perl:

    <mt:If test="length($some_variable) > 10">
        '<$mt:Var name="some_variable"$>' is 11 characters or longer
    </mt:If>

Compare two variables:

<mt:Var name="my_var1" value="foo">
<mt:TagName setvar="my_var2">

<mt:If name="my_var1" eq="$my_var2">
    Foo is equal to bar.
<mt:else>
    Foo is not equal to bar.
</mt:If>

Related

• <mt:Unless>
• <mt:Else>