Is anyone else having trouble with web browsers?

Hi guys, I am desperate for some help any advice much appreciated! I would be
interested to hear if anyone else has had this problem and how they solved it?
I am working in MX pro 2004 and Learning Action Script and behaviours and have
created a moving character based on these bits of code.

onClipEvent(enterFrame){
if (Key.isDown(Key.RIGHT)) {
_root.sprite._x += 10;
}
(and so on for the up, right and left)

onClipEvent (keyDown) {
if (Key.getCode() == Key.DOWN) {
_root.sprite.gotoAndStop(1);
_root.sprite.down.play();
}
(and so on for the up, right and left)

onClipEvent (keyUp) {
if (Key.getCode() == Key.DOWN) {
_root.sprite.down.stop();
}

Now when I publish it and view it through a browser the character "locks" she doesn't
move properly or play the correct walking animations for each key press until I click
on her! Runs fine as far as I can see when I test the movie or play it through the flash
player, but really wanted it to be eventually uploaded onto the web.

Thanks in advance