wildcards in "if then" statement

Hello,

I would like to use a simple "if then" test to check if an argument to a command begins with "http://" as follows:

if [ $2 == http://* ]; then

command
fi

but the wildcard just seems to be ignored, ie., it will only execute the command if the expression is strictly "http://" with nothing following it. I have tried enclosing the second expression with single and double quotes, and have tried using various wildcards such as ".", "?", ".*", etc. to no avail.

Any suggestions?

Thank you,

Allasso Travesser