I'm using HTML Form to send information to destination.com as follow:

<form name="form1" action=http://misi.com/misiscript method="post">
<input type="hidden" name="Login" value="My-Username">
<input type="hidden" name="Passwd" value="My-password">
<input type="hidden" name="Cust" value="Misi Misi">
<input type="hidden" name="Total" value="100">
<input type="submit" value="Submit">
</form>

This HTML Form is the only method that destination.com can accept.

But this is very big security issue, since people can use 'View Source' and get my login and username.

How to protect my login and password from being viewable to the world but the form still work ?