diff --git a/index.html b/index.html
index 105a328..c41196c 100644
--- a/index.html
+++ b/index.html
@@ -304,21 +304,20 @@ <h4 class="modal-title" id="myModalLabel">Load custom ontology</h4>
                 </button>
                 <h4 class="modal-title" id="myModalLabel">Load custom EDAM version</h4>
             </div>
-            <form action="/" method="get" onsubmit="" id="custom_version_from">
+            <form action="/" method="get" onsubmit="browser.cmd.loadCustomVersion();browser.current_branch('edam','custom'); return false;" id="custom_version_from">
                 <div class="modal-body">
                     <div class="form-group">
                         <label for="version_url">Custom Version URL</label>
-                        <input type="text" class="form-control" id="version_url" required name="url">
+                        <input type="url" class="form-control" id="version_url" required name="url" pattern=".+\.owl$">
                         <small class="form-text text-muted">You can try with https://raw.githubusercontent.com/edamontology/edamontology/main/EDAM_dev.owl</small>
                     </div>
 
                 </div>
                 <div class="modal-footer">
                     <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
-                    <button type="button" class="btn btn-primary" onclick="browser.cmd.loadCustomVersion();browser.current_branch('edam','custom')">Load
+                    <button type="submit" class="btn btn-primary" >Load
                         EDAM
                     </button>
-                    <button type="submit" style="display:none;"></button>
                 </div>
             </form>
         </div>
diff --git a/js/tree-edam-stand-alone.js b/js/tree-edam-stand-alone.js
index 776d4cb..a822de8 100644
--- a/js/tree-edam-stand-alone.js
+++ b/js/tree-edam-stand-alone.js
@@ -71,57 +71,45 @@ function interactive_edam_browser(){
                 branch='edam';
         }
         $("#edam-branches .branch."+branch).addClass("active");
-        updateVersion(version);
-        updateBranch(branch);
         //setCookie("edam_browser_branch",branch);
         current_branch=branch;
+
         //get tree from cache (either same version or a subset request)
-        if(!version || version==getCookie("edam_version","stable" )){
-            
+        if(!version){
             tree=JSON.parse(localStorage.getItem("current_edam"));
+            //cache is empty, load default version
             if(!tree){
                 version='stable';
                 tree_url=getTreeURL(version);
                 __my_interactive_tree.data_url(tree_url);
                 setCookie("edam_version",version);
             }
+            setCookie("isLoaded",true)
             __my_interactive_tree.data(tree);
         }
 
         //load version (pre-determined or custom)
         else {
+            //show loading spinner
             document.getElementById("tree").style.display = "none";          
             $(".loader-wrapper").show();
-            //in case we're passed the raw url link directly
+
+            //in case we're passed the raw url link directly, no need to map it
             if(customRe.test(version)){
                  tree_url=version;
-                 setCookie("edam_version",version);
-
-            }
-            else{
-                 tree_url=getTreeURL(version);
-                 setCookie("edam_version",version);
-
+                 setCookie("edam_version",tree_url);
             }
-            
-            if(version=='custom'){
-                version=tree_url;
+            //listed branch
+            else {
+                //maping branch to url
+                tree_url=getTreeURL(version);
                 setCookie("edam_version",version);
-            }
-
-            let uri = __my_interactive_tree.cmd.getElementByIdentifier(getInitURI(current_branch));
-            if (uri){
-                uri = __my_interactive_tree.identifierAccessor()(uri)
-                let params = ""
-                if(version!="stable"){
-                    params+="&version="+version
-                }
-                if(current_branch!="edam"){
-                    params+="&branch="+current_branch
+                if(version=='custom'){
+                    //custom branch, identify it by the url
+                    version=tree_url;
+                    setCookie("edam_version",version);
                 }
-                window.location.hash = uri.replace("http://edamontology.org/","") + params;
-
-            }    
+            }
             __my_interactive_tree.data_url(tree_url);
 
         }
@@ -131,7 +119,7 @@ function interactive_edam_browser(){
     function loadCustomVersion(){     
         $("#versionModal").modal('hide');
         let versionURL=document.getElementById('version_url').value;
-        setCookie("edam_version",versionURL);
+        setCookie("custom_url",versionURL);
        }
 
     function getTreeURL(version){
@@ -139,7 +127,7 @@ function interactive_edam_browser(){
             case 'latest':
                 return "https://raw.githubusercontent.com/edamontology/edamontology/main/EDAM_dev.owl";
             case 'custom':
-                return getCookie("edam_version","");
+                return getCookie("custom_url","");
             case 'stable':
                 return "https://raw.githubusercontent.com/edamontology/edamontology/main/releases/EDAM_1.25.owl";
             default:
@@ -286,6 +274,9 @@ function interactive_edam_browser(){
             .toLowerCase()
             .replace(/[-]+/g,'-');
             let params = ""
+            //update url only if the tree is loaded successfully
+            if(getCookie("isLoaded",true)=="true") {
+
             if(version!="stable"){
                 params+="&version="+version
             }
@@ -293,6 +284,11 @@ function interactive_edam_browser(){
                 params+="&branch="+current_branch
             }
             window.location.hash = uri.replace("http://edamontology.org/","") + params;
+
+            //update version and branch as well
+            updateVersion(version);
+            updateBranch(current_branch);
+        }
             if(current_branch!="custom_url" && window.location.search){
             setUrlParameters("");
         }
diff --git a/js/tree-reusable-d3.js b/js/tree-reusable-d3.js
index dd0a1c1..5e8f97f 100644
--- a/js/tree-reusable-d3.js
+++ b/js/tree-reusable-d3.js
@@ -872,11 +872,23 @@ var interactive_tree = function() {
 
         identifierToElement={};
         data_url = value;
-        jsonTreeFromURL(value,(tree) => {
+        jsonTreeFromURL(value,
+            //tree loaded successfully
+            (tree) => {
+            setCookie("isLoaded",true);
             localStorage.setItem("current_edam",JSON.stringify(tree))
             setCookie("edam_url",value)
             tree.meta.data_url=data_url;
             chart.data(tree);
+            }, 
+            //tree can't be loaded, restore the previous state
+            (err)=>{
+            //alert the error
+            alert('We encountered the following error: '+ err.message+". Taking you back to the previous version.");
+            //load previous version from cache
+            setCookie("isLoaded",false);
+            var tree=JSON.parse(localStorage.getItem("current_edam"));
+            chart.data(tree);
             });
     }
 
diff --git a/package.json b/package.json
index 493d689..e0d5bbd 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   },
   "devDependencies": {
     "@babel/core": "^7.14.8",
-    "@babel/preset-env": "^7.14.8",
+    "@babel/preset-env": "^7.14.9",
     "@fortawesome/fontawesome-free": "^5.15.3",
     "cssnano": "^5.0.6",
     "jshint": "^2.9.5",
@@ -20,7 +20,7 @@
   "dependencies": {
     "bootstrap": "^3.4.1",
     "d3": "^4.13.0",
-    "edam2json-js": "^0.2.2",
+    "edam2json-js": "^0.2.3",
     "ga-gtag": "^1.1.0",
     "gh-pages": "^3.2.3",
     "jquery": "^3.2.1",