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As demonstrated in the previous example it is easy to write simple tags that have no body and just output content. Another example is a `dateFormat` style tag:

[source,groovy]
----
def dateFormat(Map attrs) {
    out << new java.text.SimpleDateFormat(attrs.format).format(attrs.date)
}
----

The above uses Java's `SimpleDateFormat` class to format a date and then write it to the response. The tag can then be used within a GSP as follows:

[source,xml]
----
<g:dateFormat format="dd-MM-yyyy" date="${new Date()}" />
----

With method-based tags, attributes may also bind directly to method parameters by name when the method is explicitly marked with `@Tag`:

[source,groovy]
----
import grails.gsp.Tag

@Tag
def dateFormat(String format, Date date) {
    out << new java.text.SimpleDateFormat(format).format(date)
}
----

With simple tags sometimes you need to write HTML mark-up to the response. One approach would be to embed the content directly:

[source,groovy]
----
def formatBook(Map attrs) {
    out << "<div id=\"${attrs.book.id}\">"
    out << "Title : ${attrs.book.title}"
    out << "</div>"
}
----

Although this approach may be tempting it is not very clean. A better approach would be to reuse the link:{gspTagsRef}render.html[render] tag:

[source,groovy]
----
def formatBook(Map attrs) {
    out << render(template: "bookTemplate", model: [book: attrs.book])
}
----

And then have a separate GSP template that does the actual rendering.
