diff --git a/src/client/conversation-viewer/conversation-email.vala b/src/client/conversation-viewer/conversation-email.vala
index 17cf85c0..fddcd894 100644
--- a/src/client/conversation-viewer/conversation-email.vala
+++ b/src/client/conversation-viewer/conversation-email.vala
@@ -565,7 +565,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         Json.Generator generator = new Json.Generator();
         generator.set_root(builder.get_root());
         string js = "geary.addPrintHeaders(" + generator.to_data(null) + ");";
-        yield this.primary_message.run_javascript(js, null);
+        yield this.primary_message.evaluate_javascript(js, null);
 
         Gtk.Window? window = get_toplevel() as Gtk.Window;
         WebKit.PrintOperation op = this.primary_message.new_print_operation();
diff --git a/src/client/conversation-viewer/conversation-message.vala b/src/client/conversation-viewer/conversation-message.vala
index 722ce090..d1b3d2ed 100644
--- a/src/client/conversation-viewer/conversation-message.vala
+++ b/src/client/conversation-viewer/conversation-message.vala
@@ -672,10 +672,10 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         return new WebKit.PrintOperation(web_view);
     }
 
-    public async void run_javascript (string script, Cancellable? cancellable) throws Error {
+    public async void evaluate_javascript(string script, Cancellable? cancellable) throws Error {
         if (this.web_view == null)
             initialize_web_view();
-        yield web_view.run_javascript(script, cancellable);
+        yield web_view.evaluate_javascript(script, -1, null, null, cancellable);
     }
 
     public void zoom_in() {
diff --git a/test/client/components/components-web-view-test-case.vala b/test/client/components/components-web-view-test-case.vala
index 08d94588..9f5db70f 100644
--- a/test/client/components/components-web-view-test-case.vala
+++ b/test/client/components/components-web-view-test-case.vala
@@ -49,10 +49,10 @@ public abstract class Components.WebViewTestCase<V> : TestCase {
         }
     }
 
-    protected WebKit.JavascriptResult run_javascript(string command) throws Error {
+    protected JSC.Value? run_javascript(string command) throws Error {
         WebView view = (WebView) this.test_view;
-        view.run_javascript.begin(command, null, this.async_completion);
-        return view.run_javascript.end(async_result());
+        view.evaluate_javascript.begin(command, -1, null, null, null, this.async_completion);
+        return view.evaluate_javascript.end(async_result());
     }
 
 }
diff --git a/test/js/components-page-state-test.vala b/test/js/components-page-state-test.vala
index bf952416..beedf3fa 100644
--- a/test/js/components-page-state-test.vala
+++ b/test/js/components-page-state-test.vala
@@ -160,7 +160,6 @@ class Components.PageStateTest : WebViewTestCase<WebView> {
         throws GLib.Error {
         string? result = Util.JS.to_string(
             run_javascript("geary.testResult")
-            .get_js_value()
         );
         assert_equal(result, expected);
     }
diff --git a/test/js/composer-page-state-test.vala b/test/js/composer-page-state-test.vala
index 5a0a8b3c..85634fea 100644
--- a/test/js/composer-page-state-test.vala
+++ b/test/js/composer-page-state-test.vala
@@ -47,7 +47,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
                 Util.JS.to_string(
                     run_javascript(
                         @"ComposerPageState.htmlToText(window.document.body);"
-                    ).get_js_value()
+                    )
                 ) == "para\n\n\n\n"
             );
         } catch (Util.JS.Error err) {
@@ -67,7 +67,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
                 Util.JS.to_string(
                     run_javascript(
                         "ComposerPageState.htmlToText(window.document.body);"
-                    ).get_js_value()
+                    )
                 ) == @"pre\n\n$(q_marker)quote\n$(q_marker)\npost\n\n\n\n"
             );
         } catch (Util.JS.Error err) {
@@ -87,7 +87,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
                 Util.JS.to_string(
                     run_javascript(
                         "ComposerPageState.htmlToText(window.document.body)"
-                    ).get_js_value()
+                    )
                 ) == @"pre\n\n$(q_marker)quote1\n$(q_marker)\n$(q_marker)$(q_marker)quote2\n$(q_marker)$(q_marker)\npost\n\n\n\n"
             );
         } catch (Util.JS.Error err) {
@@ -106,7 +106,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
                 Util.JS.to_string(
                     run_javascript(
                         "ComposerPageState.htmlToText(window.document.body, [\"blockquote\"])"
-                    ).get_js_value()
+                    )
                 ) == @"pre\n\npost\n\n\n\n"
             );
         } catch (Util.JS.Error err) {
@@ -126,7 +126,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
             assert(
                 Util.JS.to_string(
                     run_javascript(@"new EditContext(document.getElementById('test')).encode()")
-                    .get_js_value()
+
                 ).has_prefix("1;url;"));
         } catch (Util.JS.Error err) {
             print("Util.JS.Error: %s\n", err.message);
@@ -145,7 +145,7 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
             assert(
                 Util.JS.to_string(
                     run_javascript(@"new EditContext(document.getElementById('test')).encode()")
-                    .get_js_value()
+
                 ) == "0;;Comic Sans;144;rgb(255, 127, 1)");
         } catch (Util.JS.Error err) {
             print("Util.JS.Error: %s\n", err.message);
@@ -164,13 +164,13 @@ class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
             assert(
                 Util.JS.to_int32(
                     run_javascript(@"document.querySelectorAll('blockquote[type=cite]').length")
-                    .get_js_value()
+
                 ) == 1
             );
             assert(
                 Util.JS.to_string(
                     run_javascript(@"document.querySelectorAll('blockquote[type=cite]').item(0).innerText")
-                    .get_js_value()
+
                 ) == "some text"
             );
         } catch (Util.JS.Error err) {
@@ -197,25 +197,25 @@ some text
             assert(
                 Util.JS.to_bool(
                     run_javascript(@"geary.containsAttachmentKeyword(\"some\", \"subject text\");")
-                    .get_js_value()
+
                 )
             );
             assert(
                 Util.JS.to_bool(
                     run_javascript(@"geary.containsAttachmentKeyword(\"subject\", \"subject text\");")
-                    .get_js_value()
+
                 )
             );
             assert(
                 !Util.JS.to_bool(
                     run_javascript(@"geary.containsAttachmentKeyword(\"innerquote\", \"subject text\");")
-                    .get_js_value()
+
                 )
             );
             assert(
                 !Util.JS.to_bool(
                     run_javascript(@"geary.containsAttachmentKeyword(\"outerquote\", \"subject text\");")
-                    .get_js_value()
+
                 )
             );
         } catch (Util.JS.Error err) {
@@ -260,7 +260,7 @@ I can send email through smtp.gmail.com:587 or through <a href="https://www.gmai
         run_javascript("geary.cleanContent();");
         string result = Util.JS.to_string(
             run_javascript("window.document.body.innerHTML;")
-            .get_js_value()
+
         );
         assert_equal(result, DIRTY_BODY_TEMPLATE.printf(expected));
     }
@@ -270,7 +270,7 @@ I can send email through smtp.gmail.com:587 or through <a href="https://www.gmai
         load_body_fixture(html);
         try {
             string result = Util.JS.to_string(
-                run_javascript(@"window.geary.getHtml();").get_js_value()
+                run_javascript(@"window.geary.getHtml();")
             );
             assert(result == CLEAN_BODY_TEMPLATE.printf(html));
         } catch (Util.JS.Error err) {
@@ -288,7 +288,7 @@ I can send email through smtp.gmail.com:587 or through <a href="https://www.gmai
             assert(
                 Util.JS.to_string(
                     run_javascript(@"window.geary.getText();")
-                    .get_js_value()
+
                 ) == "para\n\n\n\n"
             );
         } catch (Util.JS.Error err) {
@@ -308,73 +308,73 @@ I can send email through smtp.gmail.com:587 or through <a href="https://www.gmai
             // Doesn't contain
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('notcontained', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('not contained', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('not\tcontained', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('http://www.keyword1.com', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('http://www.something.com/something.sf1', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('sf1', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('.sf1', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
 
             // Does contain
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('keyword1', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('keyword2 contained', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('keyword2\tcontained', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('keyword1.', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('something.sf1', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('something.something.sf2', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
             assert(!Util.JS.to_bool(run_javascript(
                 @"ComposerPageState.containsKeywords('http://something/else.sf2', $complete_keys, $suffix_keys);"
-                ).get_js_value()
+                )
             ));
 
         } catch (Util.JS.Error err) {
@@ -394,12 +394,12 @@ I can send email through smtp.gmail.com:587 or through <a href="https://www.gmai
             assert(
                 Util.JS.to_string(
                     run_javascript(@"ComposerPageState.replaceNonBreakingSpace('$(single_nbsp)');")
-                    .get_js_value()
+
                 ) == "a b");
             assert(
                 Util.JS.to_string(
                     run_javascript(@"ComposerPageState.replaceNonBreakingSpace('$(multiple_nbsp)');")
-                    .get_js_value()
+
                 ) == "a b c");
         } catch (Util.JS.Error err) {
             print("Util.JS.Error: %s\n", err.message);
diff --git a/test/js/conversation-page-state-test.vala b/test/js/conversation-page-state-test.vala
index e46783e3..fc460886 100644
--- a/test/js/conversation-page-state-test.vala
+++ b/test/js/conversation-page-state-test.vala
@@ -109,7 +109,6 @@ class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView
                         document.getElementById('test'), "BLOCKQUOTE"
                     );
                 """)
-                .get_js_value()
            )
         );
     }
@@ -123,7 +122,6 @@ class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView
                         document.getElementById('test'), "BLOCKQUOTE", "test-class"
                     );
                 """)
-                .get_js_value()
            )
         );
     }
@@ -137,7 +135,6 @@ class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView
                         document.getElementById('test'), "DIV"
                     );
                 """)
-                .get_js_value()
            )
         );
     }
@@ -151,7 +148,6 @@ class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView
                         document.getElementById('test'), "DIV", null, false
                     );
                 """)
-                .get_js_value()
            )
         );
     }
@@ -167,7 +163,6 @@ class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView
         try {
             ret = (uint) Util.JS.to_int32(
                 run_javascript(@"ConversationPageState.isDeceptiveText(\"$text\", \"$href\")")
-                .get_js_value()
             );
         } catch (Util.JS.Error err) {
             print("Util.JS.Error: %s\n", err.message);