Fixed the ability to interact with a SerialPort control on iOS devices

modules/pcjs/lib/keyboard.js

@@ -345,6 +345,16 @@ Keyboard.SIMCODE = {
     ALT:          Keyboard.KEYCODE.ALT         + Keyboard.KEYCODE.ONDOWN,
     CAPS_LOCK:    Keyboard.KEYCODE.CAPS_LOCK   + Keyboard.KEYCODE.ONDOWN,
     ESC:          Keyboard.KEYCODE.ESC         + Keyboard.KEYCODE.ONDOWN,
+    /*
+     * It seems that a recent change to Safari on iOS (first noticed in iOS 9.1) treats SPACE
+     * differently now, at least with regard to <textarea> controls, and possibly only readonly
+     * or hidden controls, like the hidden <textarea> we overlay on the Video <canvas> element.
+     *
+     * Whatever the exact criteria are, Safari on iOS now performs SPACE's default behavior
+     * after the onkeydown event but before the onkeypress event.  So we must now process SPACE
+     * as an ONDOWN key, so that we can call preventDefault() and properly simulate the key at
+     * the time the key goes down.
+     */
     SPACE:        Keyboard.KEYCODE.SPACE       + Keyboard.KEYCODE.ONDOWN,
     F1:           Keyboard.KEYCODE.F1          + Keyboard.KEYCODE.ONDOWN,
     F2:           Keyboard.KEYCODE.F2          + Keyboard.KEYCODE.ONDOWN,

modules/pcjs/lib/serialport.js

@@ -343,16 +343,6 @@ SerialPort.prototype.setBinding = function(sHTMLType, sBinding, control)
 
     switch (sBinding) {
     case SerialPort.sIOBuffer:
-        /*
-         * TODO: Figure out how to make this control activate the soft keyboard on iOS; since
-         * this control has the "readonly" attribute by default, iOS refuses to activate the
-         * keyboard, and adding the "contenteditable" attribute doesn't override that behavior.
-         *
-         * Removing the "readonly" attribute works, but then every key press results in double
-         * characters; presumably that could be overcome by processing all keys in the onKeyDown()
-         * handler instead, but that would require keyCode mapping tables, because down events
-         * are not the same as press events.
-         */
         this.bindings[sBinding] = this.controlIOBuffer = control;
 
         /*
@@ -380,33 +370,33 @@ SerialPort.prototype.setBinding = function(sHTMLType, sBinding, control)
             }
             return true;
         };
+
         control.onkeypress = function onKeyPress(event) {
             /*
-             * Browser-independent keyCode extraction; refer to keyPress() and the other key event
+             * Browser-independent keyCode extraction; refer to onKeyPress() and the other key event
              * handlers in keyboard.js.
              */
             event = event || window.event;
             var keyCode = event.which || event.keyCode;
             serial.sendRBR([keyCode]);
             /*
-             * This additional check for SPACE (keyCode 0x20) and subsequent preventDefault()
+             * Since we're going to remove the "readonly" attribute from the <textarea> control
-             * prevents SPACE from bubbling up to the document event handlers, where the default
+             * (so that the soft keyboard activates on iOS), instead of calling preventDefault() for
-             * behavior is typically to scroll the entire page -- a real nuisance.
+             * selected keys (eg, the SPACE key, whose default behavior is to scroll the page), we must
-             *
+             * now call it for *all* keys, so that the keyCode isn't added to the control immediately,
-             * Keyboard.onKeyPress() has a similar issue, but it seems to be limited to Safari on iOS,
+             * on top of whatever the machine is echoing back, resulting in double characters.
-             * first noticed on iOS 9.1.  The problem there is that Safari's default SPACE behavior
-             * occurs BEFORE the onkeypress handler is called, so we would have to call preventDefault()
-             * in the onkeydown handler, but then the onkeypress handler would no longer be called.
-             *
-             * So, to resolve the Keyboard.onKeyPress() issue, we now define SPACE as an ONDOWN key,
-             * so that onKeyDown() will process the SPACE key immediately and automatically invoke
-             * preventDefault().
              */
-            if (keyCode == 0x20) {
+            if (event.preventDefault) event.preventDefault();
-                if (event.preventDefault) event.preventDefault();
-            }
             return true;
         };
+
+        /*
+         * Now that we've added an onkeypress handler that calls preventDefault() for ALL keys, the control
+         * itself no longer needs the "readonly" attribute; we primarily need to remove it for iOS browsers,
+         * so that the soft keyboard will activate, but it shouldn't hurt to remove the attribute for all browsers.
+         */
+        control.removeAttribute("readonly");
+
         return true;
 
     default: