Detecting the sliding movement end gesture

// sliding direction detection 
var the startx, startY; 
// get the angle 
function getAngle (angx, Angy) { 
    return Math.atan2 (Angy, angx) * 180 [/ Math.PI; 
}; 

// returns the start and end points according to an upward direction 2 left right 0 3 4 down No sliding 
function for getDirection (the startx, startY, EndX, Endy) { 
    var = angx EndX - the startx; 
    var = Endy Angy - startY; 
    var Result = 0; 

    // if the slide distance is too short 
    if (the Math.abs (angx) <2 && the Math.abs (Angy) <2) { 
        return Result; 
    } 

    var angle = getAngle (angx, Angy); 
    IF (angle> = -135 && angle <= -45) { 
        Result . 1 =; 
    } the else IF (angle> 45 && angle <135) { 
        Result = 2;
    } else if ((angle >= 135 && angle <= 180) || (angle >= -180 && angle < -135)) {
        result = 3;
    } else if (angle >= -45 && angle <= 45) {
        result = 4;
    }

    return result;
}
//手指接触屏幕
document.addEventListener("touchstart", function(e) {
    startx = e.touches[0].pageX;
    starty = e.touches[0].pageY;
}, false);
//手指离开屏幕
document.addEventListener("touchend", function(e) {
    var endx, endy;
    endx = e.changedTouches[0].pageX;
    endy = e.changedTouches[0].pageY;
    var direction = getDirection(startx, starty, endx, endy);
    if(self.show)
    switch (direction) {
        0 Case: 
            // Alert ( "not slide!"); 
            BREAK; 
        Case. 1: 
            // Alert ( "Up!"); 
            BREAK; 
        Case 2: 
            // Alert ( "Down!"); 
            BREAK; 
        Case. 3: 
            // alert ( "left!"); 
            BREAK; 
        Case. 4: 
            self.cutImg (-1); 
            BREAK; 
        default: 
    } 
}, to false);