disable submit button when login form is validated

login_form.php

@@ -50,6 +50,8 @@ function validateLoginForm(f) {
 			return false;
 		}
 
+		document.forms['loginForm']['click'].disabled = true;
+
 		return true;
 	} catch (e) {
 		exception_error("validateLoginForm", e);
@@ -97,7 +99,7 @@ window.onload = init;
 				<label for="remember_me">Remember me on this computer</label>
 			</td></tr> -->
 			<tr><td colspan="2" align="right" class="innerLoginCell">
-			<input type="submit" class="button" value="<?php echo __('Login') ?>" name='click'>
+			<input type="submit" class="button" value="<?php echo __('Log in') ?>" name='click'>
 				<input type="hidden" name="action" value="login">
 				<input type="hidden" name="rt" 
 					value="<?php if ($return_to != 'none') { echo $return_to; } ?>">