UI 4.6 - How to make a button OnClickDown rather than just OnClick

I have this script thats meant to move a sprite around the scene. It works but I have to keep clicking the button to move the sprite around rather than just hold the mouse down over the button. How do I change it so I can hold the mouse down over the button and have the sprite move.

var player : GameObject;
var speed : int;

function Up() {
player.transform.Translate(Vector2(0,1) * speed);

}

function Down() {
player.transform.Translate(Vector2(0,-1) * speed);

}

function Left() {
player.transform.Translate(Vector2(-1,0) * speed);

}

function Right() {
player.transform.Translate(Vector2(1,0) * speed);

Instead of using the button’s default event, put a component called “Event Trigger” onto your object that has the button script on it. Next, click “add new event type” and click “OnPointerDown.”

Then just drag your GO in like normal and select the function to be called.