Update templates/index.html

templates/index.html

@@ -443,8 +443,7 @@
         const input = event.target;
         let value = input.value;
 
-        // Remove all characters except digits and decimal point
-        value = value.replace(/[^0-9.]/g, "");
+        value = value.replace(/[^0-9.-]/g, "");
 
         // Remove multiple decimal points
         const parts = value.split(".");