Character Jump with Animation - actionscript-3

Question

Im trying to create a platform game but im struggling with the jump part of the game. I have got the jump working but when I try to add the animation it goes all wrong. When I hit the jump button it jumps but when i lands it gets stuck on the end of the jump animation until i move. Secondly when i jump and press the right or left button it jumps but plays the run animation while i try to move in mid air. How can i resolve these problems
package
{
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
public class Player extends MovieClip
{
//Player run speed setting
var RunSpeed:Number = 8;
//Player key presses
var RightKeyPress:Boolean = false;
var LeftKeyPress:Boolean = false;
var UpKeyPress:Boolean = false;
//Jump variables
var Gravity:Number = 1.5;
var Yvelocity:Number = 0;
var CanJump:Boolean = false;
public function Player()
{
// constructor code
stage.addEventListener(KeyboardEvent.KEY_DOWN, KeyPressed);
addEventListener(Event.ENTER_FRAME, Update);
stage.addEventListener(KeyboardEvent.KEY_UP, KeyReleased);
}
function KeyPressed(event:KeyboardEvent)
{
//When Key is Down
if (event.keyCode == 39)
{
RightKeyPress = true;
}
if (event.keyCode == 37)
{
LeftKeyPress = true;
}
if (event.keyCode == 38)
{
UpKeyPress = true;
}
}
function Update(event:Event)
{
//Adding gravity to the game world
Yvelocity += Gravity;
//if player is more than 300 on the y-axis
if (this.y > 300)
{
//Player stays on the ground and can jump
Yvelocity = 0;
CanJump = true;
}
if ((RightKeyPress == true))
{
x += RunSpeed;
gotoAndStop('Run');
scaleX = 1;
}
else if ((LeftKeyPress == true))
{
x -= RunSpeed;
gotoAndStop('Run');
scaleX = -1;
}
if ((UpKeyPress == true && CanJump))
{
Yvelocity = -15;
CanJump = false;
gotoAndStop('Jump');
}
this.y += Yvelocity;
}
function KeyReleased(event:KeyboardEvent)
{
if (event.keyCode == 39)
{
event.keyCode = 0;
RightKeyPress = false;
gotoAndStop('Idle');
}
if (event.keyCode == 37)
{
event.keyCode = 0;
LeftKeyPress = false;
gotoAndStop('Idle');
}
if (event.keyCode == 38)
{
event.keyCode = 0;
UpKeyPress = false;
}
}
}
}

Answer 1

this.y > 300, that is your jump end logic. Add a gotoAndStop('Idle'); in that if's block.

Answer 2

Just Check if canJump is true on your left and right keypresses before executing those blocks. If canJump is true allow the running stuff