Help with jumping script

programming
1

Im trying to make a mario type game and can’t seem to get the jumping to work the way I want. I want the character to jump of course, but I want the jump to be key sensitive. I want the character to jump higher when the button is held longer. The code I have works, until you press the key twice while the character is in mid jump. The character will fall down further then what it should fall. I know the problem is with my countHeight variable which adds to the height of the jump when the key is held down. Can anybody help me come up with a better script that is fool proof?

onClipEvent(load)
{
var count = 0;
var countHeight = 0;
var jump = false;
var jumpLevel = 2;
var jumpY = -9;
}

onClipEvent(enterFrame)
{
if(key.isDown(Key.CONTROL))
{
if(countHeight != 9)
countHeight ++;
if(jump != true)
jump = true;
}

            if(jump)
            {
                count ++;
            	this._y += jumpY;
            	if(count == jumpLevel+countHeight)
                {
	                jumpY = -jumpY;
            	}
                if(count == 2*(jumpLevel+countHeight))
            	{
                	jumpY = -jumpY;
            		count = 0;
                	jump = false;
            	}
            }
            else
                countHeight = 0;

}