HTML/PHP FORM VALIDATION : 
i am new to php and i learnt about it via tutorials . (thanks to youtube).

my only doubt is this ..

i have a textbox in form,which i want to validate as follows:

**TextField name= enrollment Id**

Enrollment id is 10 in length and is of pattern like TCA1409032 (starting three index are characters,Can be TCA,TEN and many more) and the rest 7 are digits.

**How do i perform this validation in my form?**