add some javascripts

add some javascripts

javascript/viewer.js

@@ -0,0 +1,37 @@
+window.main_viewer_height = 512;
+
+function resized() {
+    let windowHeight = window.innerHeight - 260;
+    let elements = document.getElementsByClassName('main_view');
+
+    if (windowHeight > 745) windowHeight = 745;
+
+    for (let i = 0; i < elements.length; i++) {
+        elements[i].style.height = windowHeight + 'px';
+    }
+
+    window.main_viewer_height = windowHeight;
+}
+
+function viewer_to_top(delay = 100) {
+    setTimeout(() => window.scrollTo({top: 0, behavior: 'smooth'}), delay);
+}
+
+function viewer_to_bottom(delay = 100) {
+    let element = document.getElementById('positive_prompt');
+    let yPos = window.main_viewer_height;
+
+    if (element) {
+        yPos = element.getBoundingClientRect().top + window.scrollY;
+    }
+
+    setTimeout(() => window.scrollTo({top: yPos - 8, behavior: 'smooth'}), delay);
+}
+
+window.addEventListener('resize', (e) => {
+    resized();
+});
+
+onUiLoaded(async () => {
+    resized();
+});