better restock js

does magic with reading barcodes

fixes #104

chezbetty/static/js/chezbetty-admin-item.js

@@ -1,8 +1,25 @@
 
 // Callback when scanner input is detected and read
-$("#scanner").bind("scannerDetectionComplete", function (e, data) {
+$("body").bind("scannerDetectionComplete", function (e, data) {
 	add_item(data.string);
-})
+});
+
+// "Errors" are really just things that didn't turn out to be barcodes
+// Add them to currently selected thing
+$("body").bind("scannerDetectionError", function (e, data) {
+	var focused = $(':focus');
+	var cursor_pos = document.getElementById(focused.attr("id")).selectionStart;
+	var cursor_end = document.getElementById(focused.attr("id")).selectionEnd;
+	var start = focused.val();
+	focused.val(start.substring(0, cursor_pos) + data.string + start.substring(cursor_end));
+
+	// Put the cursor back where it was.
+	document.getElementById(focused.attr("id")).selectionStart = cursor_pos + data.string.length;
+	document.getElementById(focused.attr("id")).selectionEnd = cursor_pos + data.string.length;
+
+	// Trigger the input change
+	focused.trigger("input");
+});
 
 // Register the scanner detector
-$("#scanner").scannerDetection();
+$("body").scannerDetection({preventDefault:true});