start using `<template>' tag

1 files changed, 20 insertions, 1 deletions

diff --git a/html/DOM_helpers.js b/html/DOM_helpers.js
index 2bff966..392299f 100644
--- a/html/DOM_helpers.js
+++ b/html/DOM_helpers.js
@@ -10,9 +10,27 @@ function by_id(id)
     return document.getElementById(id);
 }
 
+const known_templates = new Map();
+
+function get_template(template_id)
+{
+    let template = known_templates.get(template_id) || null;
+    if (template)
+	return template;
+
+    for (const template_node of document.getElementsByTagName("TEMPLATE")) {
+	template = template_node.content.getElementById(template_id);
+	if (template)
+	    break;
+    }
+
+    known_templates.set(template_id, template);
+    return template;
+}
+
 function clone_template(template_id)
 {
-    const clone = document.getElementById(template_id).cloneNode(true);
+    const clone = get_template(template_id).cloneNode(true);
     const result_object = {};
     const to_process = [clone];
 
@@ -36,6 +54,7 @@ function clone_template(template_id)
 /*
  * EXPORTS_START
  * EXPORT by_id
+ * EXPORT get_template
  * EXPORT clone_template
  * EXPORTS_END
  */