Add windows

js/window.js

@@ -0,0 +1,29 @@
+// TODO: Rewrite to support more than one window per page.
+
+const subwindow = document.getElementById("window");
+const titlebar = document.getElementById("window-titlebar");
+
+let dragging = false;
+let prevPosX;
+let prevPosY;
+
+titlebar.addEventListener("mousedown", (event) => {
+    dragging = true;
+    prevPosX = event.clientX;
+    prevPosY = event.clientY;
+});
+
+window.addEventListener("mousemove", (event) => {
+    if (!dragging)
+        return;
+    const newPosX = subwindow.offsetLeft - (prevPosX - event.clientX);
+    const newPosY = subwindow.offsetTop  - (prevPosY - event.clientY);
+    subwindow.style.left = newPosX + "px";
+    subwindow.style.top  = newPosY + "px";
+    prevPosX = event.clientX;
+    prevPosY = event.clientY;
+});
+
+window.addEventListener("mouseup", (_event) => {
+    dragging = false;
+});