Hi sandeep

Yes diploma student also give JE exam but they will not eligable in the basics of jee main score.they will be eligable only on iits after qualifying jee advance . For that fisrt you have to clear jee main then jee advance 

Thank you

Yes, Diploma Students can apply for JEE Main Entrance Exam but they will not be eligible to get admission on the basis of JEE Main score, They will be eligible only to get admission in IITs after qualifying JEE Advance so first you need to apply JEE Main, to qualify it you need to go for JEE Advance as the procedure of admission.

Good Luck!