return is for sending the results of a function call back to the function or script that called it. It's the opposite of passing parameters to a function.
What you're doing is looping over a variable in the same scope, so return is not needed. Printing is done via echo or print. However, you may choose to build a value in that loop and print that once the loop is completed.
Additionally, if you're in a loop and you want to stop that loop immediately, use break; and if you want to skip the iteration you're on and go to the next one, use continue.
Here's some additional reading.
More clarification on continue. Say, for whatever reason, we don't want to do anything when $i is 6:
$start = 1;
$end = 11;
for ($i = $start; $i < $end; $i++)
// changed this to iterate over $i for readability/clarity
{
if ($start == 6)
{
// essentially, continue just skips this iteration of
// the loop, goes back to the top, iterates $i based on
// that third parameter in the for() declaration, and
// continues on.
continue;
}
echo $start; //how can I use return?
}
// output: 1234578910
echo?