losing focus drops piece

js/scripts.min.js

@@ -1,9 +1,18 @@
+
+
 function Vector() {}
 
 function Line() {}
 
 function Matrix() {}
 
+var oob = false;
+
+document.getElementById("app").onmouseleave = function(){
+    oob = true;
+};
+
+
 function checkTouch() {
     var a = document.createElement("div");
     return a.setAttribute("ontouchmove", "return;"), typeof a.ontouchmove == "function" ? !0 : !1
@@ -19,11 +28,16 @@ function initControls() {
 }
 
 function grabPiece(a) {
-    !mouseDown && controls && (a.preventDefault(), mouseDown = !0, grabbed = this, grabbedID = grabbed.id.substr(-2), startX = a.pageX - document.body.offsetWidth / 2, startY = a.pageY - document.body.offsetHeight / 2, style = window.getComputedStyle(grabbed), matrix = style.getPropertyValue("-webkit-transform"), matrixParts = matrix.split(","), grabbedW = parseInt(style.getPropertyValue("width")) / 2, grabbedX = parseInt(matrixParts[4]), grabbedY = parseInt(matrixParts[5]), grabbed.classList.add("grabbed"), showMoves(grabbedID), highLight(grabbed, square))
+    !mouseDown &&  controls && (a.preventDefault(), mouseDown = !0, grabbed = this, grabbedID = grabbed.id.substr(-2), startX = a.pageX - document.body.offsetWidth / 2, startY = a.pageY - document.body.offsetHeight / 2, style = window.getComputedStyle(grabbed), matrix = style.getPropertyValue("-webkit-transform"), matrixParts = matrix.split(","), grabbedW = parseInt(style.getPropertyValue("width")) / 2, grabbedX = parseInt(matrixParts[4]), grabbedY = parseInt(matrixParts[5]), grabbed.classList.add("grabbed"), showMoves(grabbedID), highLight(grabbed, square))
 }
 
 function dragPiece(a) {
+    if(oob){
+        dropPiece(a);
+        oob=false;
+    }else{
     mouseDown && controls && (a.preventDefault(), moveX = a.pageX - document.body.offsetWidth / 2, moveY = a.pageY - document.body.offsetHeight / 2, distX = moveX - startX, distY = moveY - startY, currentColor === "w" ? (newX = grabbedX + distX, newY = grabbedY + distY) : (newX = -(grabbedX + distX), newY = -(grabbedY + distY)), grabbed.style.webkitTransform = "translateX(" + newX + "px) translateY(" + newY + "px) translateZ(2px)", highLight(grabbed, square))
+    }
 }
 
 function dropPiece(a) {