javascript - How to know if the user input a registered valid email address exists -

javascript - How to know if the user input a registered valid email address exists -

i want create registration form email required user should input valid registered email address if not registration not complete. how do that?

example:

<form> <input type="email" name="email" required="required" /> <input type="submit" value="submit" name="submit" /> </form>

if don't want usual approval loop selection paying online service, like:

http://verify-email.org/using-api.html

they say:

looking verify email? email verification tool connects mail service server , checks whether mailbox exists or not.

what beingness verified: format: "name@domain.xxx" valid domain: "somebody@new.york" not valid valid user: verify if user , mailbox exist

disclaimer: i'm not in way connected them, advertising not intent. there might similar free services, not trust those, since harvesting email addresses. free cheese in mousetrap.

javascript php jquery html email