PHP - if html commenting
===

I would like to hide part of a pages content depending on the url.

at the moment if I typed:

example.co.uk/index.php?brand=apple

then the apple content will show - however there is some default div's on the page that I'd like to hide if no brand was shown.

I was thinking along the lines of:

        <?php if brand==""
    echo "<!----- comment out all the default HTML"
    />
    
    default html here
    
    <?php if brand==""
    echo "-->"
    />


Would that be the correct way to go about clearing the page if no brand was mentioned in the url?