diff --git a/sphinxcontrib/mermaid.py b/sphinxcontrib/mermaid.py
index ccec878..798e7c6 100644
--- a/sphinxcontrib/mermaid.py
+++ b/sphinxcontrib/mermaid.py
@@ -411,6 +411,10 @@ def install_js(
     context: dict,
     doctree: nodes.document | None,
 ) -> None:
+    # Skip when not emitting raw Mermaid diagrams which need rendering
+    if app.config.mermaid_output_format != "raw":
+        return
+
     # Skip for pages without Mermaid diagrams
     if doctree and not doctree.next_node(mermaid):
         return
@@ -432,53 +436,52 @@ def install_js(
         )
         app.add_js_file(None, body=app.config.mermaid_init_js, priority=priority)
 
-    if app.config.mermaid_output_format == "raw":
-        if app.config.mermaid_d3_zoom:
+    if app.config.mermaid_d3_zoom:
+        _d3_js_url = "https://unpkg.com/d3/dist/d3.min.js"
+        _d3_js_script = """
+        window.addEventListener("load", function () {
+          var svgs = d3.selectAll(".mermaid svg");
+          svgs.each(function() {
+            var svg = d3.select(this);
+            svg.html("<g>" + svg.html() + "</g>");
+            var inner = svg.select("g");
+            var zoom = d3.zoom().on("zoom", function(event) {
+              inner.attr("transform", event.transform);
+            });
+            svg.call(zoom);
+          });
+        });
+        """
+        app.add_js_file(_d3_js_url, priority=app.config.mermaid_js_priority)
+        app.add_js_file(None, body=_d3_js_script, priority=app.config.mermaid_js_priority)
+    elif doctree:
+        mermaid_nodes = doctree.findall(mermaid)
+        _d3_selector = ""
+        for mermaid_node in mermaid_nodes:
+            if "zoom_id" in mermaid_node:
+                _zoom_id = mermaid_node["zoom_id"]
+                if _d3_selector == "":
+                    _d3_selector += f".mermaid#{_zoom_id} svg"
+                else:
+                    _d3_selector += f", .mermaid#{_zoom_id} svg"
+        if _d3_selector != "":
             _d3_js_url = "https://unpkg.com/d3/dist/d3.min.js"
-            _d3_js_script = """
-            window.addEventListener("load", function () {
-              var svgs = d3.selectAll(".mermaid svg");
-              svgs.each(function() {
+            _d3_js_script = f"""
+            window.addEventListener("load", function () {{
+              var svgs = d3.selectAll("{_d3_selector}");
+              svgs.each(function() {{
                 var svg = d3.select(this);
                 svg.html("<g>" + svg.html() + "</g>");
                 var inner = svg.select("g");
-                var zoom = d3.zoom().on("zoom", function(event) {
+                var zoom = d3.zoom().on("zoom", function(event) {{
                   inner.attr("transform", event.transform);
-                });
+                }});
                 svg.call(zoom);
-              });
-            });
+              }});
+            }});
             """
             app.add_js_file(_d3_js_url, priority=app.config.mermaid_js_priority)
             app.add_js_file(None, body=_d3_js_script, priority=app.config.mermaid_js_priority)
-        elif doctree:
-            mermaid_nodes = doctree.findall(mermaid)
-            _d3_selector = ""
-            for mermaid_node in mermaid_nodes:
-                if "zoom_id" in mermaid_node:
-                    _zoom_id = mermaid_node["zoom_id"]
-                    if _d3_selector == "":
-                        _d3_selector += f".mermaid#{_zoom_id} svg"
-                    else:
-                        _d3_selector += f", .mermaid#{_zoom_id} svg"
-            if _d3_selector != "":
-                _d3_js_url = "https://unpkg.com/d3/dist/d3.min.js"
-                _d3_js_script = f"""
-                window.addEventListener("load", function () {{
-                  var svgs = d3.selectAll("{_d3_selector}");
-                  svgs.each(function() {{
-                    var svg = d3.select(this);
-                    svg.html("<g>" + svg.html() + "</g>");
-                    var inner = svg.select("g");
-                    var zoom = d3.zoom().on("zoom", function(event) {{
-                      inner.attr("transform", event.transform);
-                    }});
-                    svg.call(zoom);
-                  }});
-                }});
-                """
-                app.add_js_file(_d3_js_url, priority=app.config.mermaid_js_priority)
-                app.add_js_file(None, body=_d3_js_script, priority=app.config.mermaid_js_priority)
 
 
 def setup(app):