how to debug in php files

calss.debug.php

    /** This function is used to debug variables during page execution
    * @param $what , the variable which need to debug,can be array or single variable
    * @param $more , to know the method and line number where that variable is used
    * @param $die , set TRUE if want to stop the page
    * how to use : debug::watch($postarray,1,1);
    * @author keshav mohta
    * @date Aug 12, 2010
    */
    class debug()
    {
    static function watch($what,$more=FALSE,$die=FALSE)
    {
    $d = debug_backtrace();
     
    if($more && isset($d[1]))
    {
    echo "<br/>METHOD:".$d[1]['class']."::".$d[1]['function'];
    echo "<br/>LINE:".$d[0]['line'];
    }
    echo "<br/>";
    if( is_array($d[0]['args'][0]) || is_object($d[0]['args'][0]) )
    {
    echo "DATA:<pre>";
    print_r($d[0]['args'][0]);
    echo "</pre>";
    }
    else
    {
    echo "Data:".$d[0]['args'][0];
    }
     
    if($die)
    {
    echo "<br/>";
    die('ends here');
    }
     
    }
    }