require_once('class/class.install.php'); //inlude apinstall class  
$install = new Installer(); //initialize it

$install->setLogPath('/home/user/public_html/apinstall'); //path to logfile
//no trailing slash!

$install->setSteps(3); //set how many steps there will be (3 in this example)

$install->defineBar('#E54000', '#E54000'); //choose colour of ( bar, text)

$install->placeholder(); //define place for your progress bar

<form id="apiform" target="progressFrame" method="post">
<input id="apisubmit" type="submit" name="submit" value="Show me how it works!"> 
					</form>

#1 step
$output = 'Sending mails'; //title of this process
$install->save($output);
/*
Process itself (f.e sending mails)
*/

#2 step
$output = 'Optimizing database';
$install->save($output);
/*
Optimizing database code
*/

//Inform user that script has finished

#3 step
$output = 'Completed';
$install->save($output);
$install->delay(5); //make delay in seconds to show finished state longer.

$install = new Installer(true); //initialize it

$install->delay(0.20); //0.2 sec of delay

$install->clearTemp(); //clear files

$install->clearTemp(true); //delete files