diff --git a/app/static/scripts/editor.js b/app/static/scripts/editor.js
index d47f216..8b7a024 100644
--- a/app/static/scripts/editor.js
+++ b/app/static/scripts/editor.js
@@ -336,12 +336,15 @@ ta.addEventListener('keydown', function(e) {
 		e.target.selectionEnd = start + 1;
 	}
 
-	// TODO
-	// Ctrl+B adds bold
-	// Ctrl+I adds italic
-	// Ctrl+U adds underline
-	
-	// Ctrl+Enter send the form
+	/*
+	 * Keybindings for buttons. The default action of the keybinding is prevented.
+	 * Ctrl+B adds bold
+	 * Ctrl+I adds italic
+	 * Ctrl+U adds underline
+	 * Ctrl+S adds strikethrough
+	 * Ctrl+H adds Header +1
+	 * Ctrl+Enter send the form
+	 */
 	if (e.ctrlKey) {
 		switch (keyCode) {
 			case 13:
@@ -354,21 +357,27 @@ ta.addEventListener('keydown', function(e) {
 				} catch(exception) {
 					t.submit.click();
 				}
+				e.preventDefault();
 				break;
 			case 66: // B
 				editor_inline(e, "bold", false);
+				e.preventDefault();
 				break;
 			case 72: // H
 				editor_title(e, 0, +1);
+				e.preventDefault();
 				break;
 			case 73: // I
 				editor_inline(e, "italic", false);
+				e.preventDefault();
 				break;
 			case 83: // S
 				editor_inline(e, "strike", false);
+				e.preventDefault();
 				break;
 			case 85: // U
 				editor_inline(e, "underline", false);
+				e.preventDefault();
 				break;
 		}
 	}