diff --git a/src/document/libdom/css.c b/src/document/libdom/css.c
index c50c22ae..cbecef0e 100644
--- a/src/document/libdom/css.c
+++ b/src/document/libdom/css.c
@@ -97,7 +97,11 @@ static css_error node_presentational_hint(void *pw, void *node,
 	return CSS_OK;
 }
 
-
+static css_error
+resolve_url_empty(void *pw, const char *base, lwc_string *rel, lwc_string **abs)
+{
+	return CSS_OK;
+}
 
 css_error
 resolve_url(void *pw, const char *base, lwc_string *rel, lwc_string **abs)
@@ -2309,3 +2313,122 @@ import_css2(struct html_context *html_context, struct uri *uri)
 //		css->import_level--;
 	}
 }
+
+void *
+el_match_selector(const char *selector, void *node)
+{
+	struct string text;
+	css_error code;
+	size_t size;
+	uint32_t count;
+	css_stylesheet_params params;
+	css_stylesheet *sheet = NULL;
+	css_select_ctx *select_ctx = NULL;
+	css_select_results *style = NULL;
+	uint8_t color_type;
+	css_color color_shade;
+
+	css_media media = {
+		.type = CSS_MEDIA_SCREEN,
+	};
+
+	css_unit_ctx unit_len_ctx = {0};
+	unit_len_ctx.viewport_width  = 800; // TODO
+	unit_len_ctx.viewport_height = 600; // TODO
+	unit_len_ctx.device_dpi = F_90; //device_dpi;
+
+	/** \todo Change nsoption font sizes to px. */
+///	f_size = FDIV(FMUL(F_96, FDIV(INTTOFIX(nsoption_int(font_size)), F_10)), F_72);
+///	f_min  = FDIV(FMUL(F_96, FDIV(INTTOFIX(nsoption_int(font_min_size)), F_10)), F_72);
+
+	unsigned int f_size = FDIV(FMUL(F_96, FDIV(INTTOFIX(50), F_10)), F_72); // TODO
+	unsigned int f_min  = FDIV(FMUL(F_96, FDIV(INTTOFIX(50), F_10)), F_72); // TODO
+
+	unit_len_ctx.font_size_default = f_size;
+	unit_len_ctx.font_size_minimum = f_min;
+	void *ret = NULL;
+
+	params.params_version = CSS_STYLESHEET_PARAMS_VERSION_1;
+	params.level = CSS_LEVEL_21;
+	params.charset = "UTF-8";
+	params.url = "foo";
+	params.title = "foo";
+	params.allow_quirks = false;
+	params.inline_style = false;
+	params.resolve = resolve_url_empty;
+	params.resolve_pw = NULL;
+	params.import = NULL;
+	params.import_pw = NULL;
+	params.color = NULL;
+	params.color_pw = NULL;
+	params.font = NULL;
+	params.font_pw = NULL;
+
+	if (!selector) {
+		return NULL;
+	}
+	if (!init_string(&text)) {
+		return NULL;
+	}
+	add_to_string(&text, selector);
+	add_to_string(&text, "{color:#123456}");
+
+	/* create a stylesheet */
+	code = css_stylesheet_create(&params, &sheet);
+
+	if (code != CSS_OK) {
+		goto empty;
+	}
+	code = css_stylesheet_append_data(sheet, (const uint8_t *) text.source, text.length);
+
+	if (code != CSS_OK && code != CSS_NEEDDATA) {
+		goto empty;
+	}
+	code = css_stylesheet_data_done(sheet);
+	if (code != CSS_OK) {
+		goto empty;
+	}
+	code = css_stylesheet_size(sheet, &size);
+
+	/* prepare a selection context containing the stylesheet */
+	code = css_select_ctx_create(&select_ctx);
+
+	if (code != CSS_OK) {
+		goto empty;
+	}
+	code = css_select_ctx_append_sheet(select_ctx, sheet, CSS_ORIGIN_AUTHOR, NULL);
+
+	if (code != CSS_OK) {
+		goto empty;
+	}
+	code = css_select_ctx_count_sheets(select_ctx, &count);
+
+	if (code != CSS_OK) {
+		goto empty;
+	}
+	code = css_select_style(select_ctx, node, &unit_len_ctx, &media, NULL, &selection_handler, 0, &style);
+
+	if (code != CSS_OK) {
+		goto empty;
+	}
+
+	color_type = css_computed_color(style->styles[CSS_PSEUDO_ELEMENT_NONE], &color_shade);
+
+	if (color_type && color_shade == 0xff123456) {
+		ret = node;
+	}
+
+empty:
+	if (style) {
+		css_select_results_destroy(style);
+	}
+	if (select_ctx) {
+		css_select_ctx_destroy(select_ctx);
+	}
+	if (sheet) {
+		css_stylesheet_destroy(sheet);
+	}
+	done_string(&text);
+
+	return ret;
+}
diff --git a/src/document/libdom/doc.h b/src/document/libdom/doc.h
index 056a2f19..d63f8044 100644
--- a/src/document/libdom/doc.h
+++ b/src/document/libdom/doc.h
@@ -11,6 +11,7 @@ struct string;
 void *document_parse_text(const char *charset, char *data, size_t length);
 void *document_parse(struct document *document, struct string *source);
 void free_document(void *doc);
+void *el_match_selector(const char *selector, void *node);
 
 #ifdef __cplusplus
 }
diff --git a/src/ecmascript/spidermonkey/document.cpp b/src/ecmascript/spidermonkey/document.cpp
index 92aaeb7f..5c379727 100644
--- a/src/ecmascript/spidermonkey/document.cpp
+++ b/src/ecmascript/spidermonkey/document.cpp
@@ -1819,6 +1819,62 @@ document_getElementsByTagName(JSContext *ctx, unsigned int argc, JS::Value *vp)
 	return true;
 }
 
+void *
+walk_tree_query(dom_node *node, char *selector, int depth)
+{
+	dom_exception exc;
+	dom_node *child;
+	void *res = NULL;
+	dom_node_type typ;
+
+	/* Only interested in element nodes */
+	exc = dom_node_get_node_type(node, &typ);
+	if (typ != DOM_ELEMENT_NODE) {
+		return NULL;
+	}
+
+	if (res = el_match_selector(selector, node)) {
+		/* There was an error; return */
+		return res;
+	}
+	/* Get the node's first child */
+	exc = dom_node_get_first_child(node, &child);
+
+	if (exc != DOM_NO_ERR) {
+		fprintf(stderr, "Exception raised for node_get_first_child\n");
+		return NULL;
+	} else if (child != NULL) {
+		/* node has children;  decend to children's depth */
+		depth++;
+
+		/* Loop though all node's children */
+		do {
+			dom_node *next_child;
+
+			/* Visit node's descendents */
+			res = walk_tree_query(child, selector, depth);
+			/* There was an error; return */
+			if (res) {
+				dom_node_unref(child);
+				return res;
+			}
+
+			/* Go to next sibling */
+			exc = dom_node_get_next_sibling(child, &next_child);
+			if (exc != DOM_NO_ERR) {
+				fprintf(stderr, "Exception raised for "
+						"node_get_next_sibling\n");
+				dom_node_unref(child);
+				return NULL;
+			}
+
+			dom_node_unref(child);
+			child = next_child;
+		} while (child != NULL); /* No more children */
+	}
+	return NULL;
+}
+
 static bool
 document_querySelector(JSContext *ctx, unsigned int argc, JS::Value *vp)
 {
@@ -1841,8 +1897,31 @@ document_querySelector(JSContext *ctx, unsigned int argc, JS::Value *vp)
 		args.rval().setNull();
 		return true;
 	}
-// TODO
-	args.rval().setNull();
+	dom_node *root = NULL; /* root element of document */
+	/* Get root element */
+	dom_exception exc = dom_document_get_document_element(document->dom, &root);
+
+	if (exc != DOM_NO_ERR) {
+		args.rval().setNull();
+		return true;
+	}
+	char *selector = jsval_to_string(ctx, args[0]);
+
+	if (!selector) {
+		dom_node_unref(root);
+		args.rval().setNull();
+		return true;
+	}
+	void *ret = walk_tree_query(root, selector, 0);
+	mem_free(selector);
+	dom_node_unref(root);
+
+	if (!ret) {
+		args.rval().setNull();
+	} else {
+		JSObject *el = getElement(ctx, ret);
+		args.rval().setObject(*el);
+	}
 
 	return true;
 }
diff --git a/test/ecmascript/assert/document.querySelector.html b/test/ecmascript/assert/document.querySelector.html
index 855ecb7d..7f21815c 100644
--- a/test/ecmascript/assert/document.querySelector.html
+++ b/test/ecmascript/assert/document.querySelector.html
@@ -11,6 +11,8 @@ function myFunction() {
 
   var y = document.querySelector('.b');
   console.assert(!(y === null), 'Class b');
+  var inp = y.innerHTML;
+  console.assert(inp === 'Class b.', 'Class b.');
 }
 
 console.error('document.querySelector.html');