You can also head to your local nursery/garden center and look to see if they have purslane. It also goes by the name Portulaca. That way, you can see it up close. But, no, purslane does not exude a white fluid. Many plants that exude white fluids tend to be toxic or, at the least, very violent combo emetic-laxatives that give everything in your stomach and bowels the "two exits, no waiting" treatment. Plants in the Euphorbia family exude a highly poisonous white sap, for example.
But, here in Northern Arizona, we don't see our wild purslane until around July or August. So we got some Portulaca from the nursery and planted it in our yard. Hopefully, it'll take over.