Assuming we are talking about PHP, specifically: Supposedly using the comma for string concatenation in php is one of the fastest ways to build a string. But unless you are doing this an awful lot, this seems like an optimization that won't buy you very much.
There are many, many ways to skin this cat, but here are a few common ones:
IN HTML:
IN PHP
Edit, you said "fastest", which I overlooked
Assuming we are talking about PHP, specifically: Supposedly using the comma for string concatenation in php is one of the fastest ways to build a string. But unless you are doing this an awful lot, this seems like an optimization that won't buy you very much.
<a href="..."> bla bla... <?php echo "string"; ?></a>