在joomla中安装组件时显示表单

I want to show a small form with JavaScript when I install component like when we install our component then after installation I just want to show a form. I have created a file that is script.commercial.php and add this file in component xml see below my code:

commercial.xml file

<scriptfile>script.commercial.php</scriptfile>
<installfile>script.commercial.php</installfile>

script.commercial.php

    <?php
defined ('_JEXEC') or die('Restricted access');
defined ('DS') or define('DS', DIRECTORY_SEPARATOR);

function install () {
    $this->cmInstall();
}

function cmInstall()
{
    echo 'Show Form here.';
    echo '<span class="installScript" id="installScript"> Click Here..!! </span>';
}

$document = JFactory::getDocument();
$document->addScript(JURI::BASE().'components/com_commercial/commercial.js');

But its not working and component install without showing this Click here or show form. How can I do this?

See Image, I want it to be like that:

I think below the joomla notes helpful for you

This is the entire script.php file