Classic Space Invaders Javascript Game on HTML page

Hi. I need someone to make a classic simple game on Javascript language, to open on a HTML page. An example of that game is here: [login to view URL] But what i want is that only 1 enemy ship spawn each time (like every 2 seconds maybe), and it disapear when your spaceship passes by it. Your spaceship can be able to shot bullets to destroy enemys too, and it can move in all directions (LEFT KEY, RIGHT KEY, UP KEY, DOWN KEY). The game ends when you colide with any enemy spaceship (the enemys DOESN´T shot bullets as in above example). Only want to count the points of enemys you destroyed or passed by. More info can be provided. Best regards.