What is the use of "value" in html form input tag??

Question

<form><input type="radio" name="gender" value="female"/>

Answer 1

it is attribute to the input tag as per ur ex which will provide value to the radio button.
when html is rendered in web browser along with the radio button it has female value as u mentioned

Answer 2

it's for send the value of the radio when we use multiples radio ( like sens value by mailto ).

<FORM>
<INPUT type= "radio" name="tarif" value="day"> day tarif
<INPUT type= "radio" name="tarif" value="night"> night tarif
<INPUT type= "radio" name="tarif" value="week-end"> week-end tarif
</FORM>