Why does a spider does not get trapped in its own web???????

Answer 1

As mentioned before, spiders have many forms of silk. In fact, there are something like 6 types among the master weaver species (those who focus the most energy on weaving, as opposed to actively hunting and so forth).

That said, spiders can and do get caught sometimes, but they can create an enzyme that dissolves their webbing (quite obviously, since they eat their webbing to recycle it.)

Answer 2

Not all the strands on the web are sticky and the spider knows which ones are not, after all she built the web.

Answer 3

Some spiders spin non-sticky web strands to walk on. There are more types, but I am not an entomologist, so hopefully, one will come along to flesh this out.