diff --git a/navig.html b/navig.html
index eebfe4d9a7e7160df7f37bf166955a6935ed518f..c7892bb574905543d3f785171b74dd521ad74875 100644
--- a/navig.html
+++ b/navig.html
@@ -31,13 +31,11 @@
 <script src="jquery-ui-1.11.4.custom/jquery-ui.js"></script>
 
 
-
+<script src="https://cdn.rawgit.com/jquery/esprima/1.2/esprima.js"></script>
 <script src="sparray.js"></script>
 <script type = "text/javascript" src="trace.js"></script>
 <script src="interp.js"></script>
 
-
-
 <style>
 .source_div {
    border-top: 1px solid black; 
diff --git a/navig.js b/navig.js
index b4dc5b7c6521531939d315e92d5ed1f07da7b840..cd9ce23f3ae84eccd06b9384f41652ef81db1b90 100644
--- a/navig.js
+++ b/navig.js
@@ -2,6 +2,7 @@
 
 var handlers = [];
 
+var parsedTree;
 
 (function(check_pred){
 
@@ -98,6 +99,7 @@ $("#navigation_step").change(function(e) {
 });
 
 $("#button_run").click(function() {
+ parsedTree = esprima.parse($("#source_code").val(), {loc:true});   
  $("#run_output").html("Run successful !");
  var timeoutID = window.setTimeout(function() { $("#run_output").html(""); }, 1000);
 });