diff --git a/main.js b/main.js
index 27ae031..32ed12f 100644
--- a/main.js
+++ b/main.js
@@ -32,9 +32,9 @@ function evaluate() {
 	}
 }
 
-let currentInput = null;
-let selectionStart = null;
-let selectionEnd = null;
+let currentInput = document.querySelector("#expr");
+let selectionStart = 0;
+let selectionEnd = 0;
 
 function setCurrentInput() {
 	currentInput = this;