JS

<?php
/* Basic solution */
$js = array();

$js[] = "/path/to/js/file.js";

foreach( $js as $value )
{
    printf( "<script type='text/javascript' src='%s'></script>\n", $value );
}

/* More complicated solution */

abstract class PageJS
{
    protected static $js = array();

    static public function add( $js, $type = "file", $group = "global" )
    {
        if( in_array( $type, array("file", "code") ) === false )
        {
            return false;
        }

        self::$js[$group][] = array( $js, $type );

        return true;
    }

    static public function display( $group = "global" )
    {
        if( empty( self::$js[$group] ) === true ) return false;

        foreach( self::$js[$group] as $value )
        {
            if( $value[1] == 'file' )
            {
                printf( "<script type='text/javascript' src='%s'></script>\n", $value[0] );
            }
            else
            {
                printf( "<script type='text/javascript>%s</script>\n", $value[0] );
            }
        }
    }
}

// Examples:

// Adding Global JS
PageJS::add( "/path/to/js/file.js" );
PageJS::add( "/path/to/js/file.js", "file" ); // Same thing as example above
PageJS::add( "
    $(function() {
        alert('Document ready!');
    });
", "code" );

// Displaying Global JS
PageJS::display();

// Adding JS for specific groups
PageJS::add( "/path/to/js/file.js", "file", "groupForCustomPage" );
PageJS::add( "
    $(function() {
        alert('Document ready!');
    });
", "code", "groupForCustomPage" );

// Displaying a custom group JS
PageJS::display(); // display the global JS
PageJS::display( "groupForCustomPage" ); // display the JS for specific page.
?>