Why onchange event taking me to new page?

Question

I am trying to populate a text field with the value of the select field. So based on the selection the text field should change. In this case, I am selecting First Name and Last name of the person and in the

option value="I have person email here"

Now, I am using onchange event on select element which calls the findemail() function. Problem is I am getting the correct emails return but it redirect me to another page and show me the value there.

Can anyone please help me?

CODE

    function findemail(e)
{
    document.getElementById('man-email-add').innerHTML=document.write(e.value);
}

HTML (I am using PHP to get all the values)

<select id="manager_detail" onchange="findemail(this.options[this.selectedIndex]);">            


<?php 

    foreach ($data['display']['userMangers'] as $manager){
      echo   $manEmail = $manager['Email'];
      echo "<option value='$manEmail'>".$manager['First_Name'].' '.$manager['Last_Name'].'  ('.$manager['Position'].')'.'</option>';
}
    
?>


                              </select>    

Redirect to new page to show the value:

Answer 1

Does it redirect to new page or reloads the same page showing the email? I believe it's doing the later as document.write(e.value); writes that value to the page. So replace document.write(e.value); with e.value;

If man-email-add is an input field, use document.getElementById('man-email-add').value=e.value;