Handle this error properly. For instance, without this, if we cannot connect to the RPC client, JSON won't be able to parse the result (there is none), in which case would cause a RuntimeException.

dist/web3-light.js

@@ -2808,8 +2808,16 @@ HttpProvider.prototype.sendAsync = function (payload, callback) {
     var request = new XMLHttpRequest();
     request.onreadystatechange = function() {
         if (request.readyState === 4) {
-            // TODO: handle the error properly here!!!
-            callback(null, JSON.parse(request.responseText));
+            var result = request.responseText;
+            var error = null;
+
+            try {
+                result = JSON.parse(result);
+            } catch(e) {
+                error = errors.InvalidResponse(result);                
+            }
+
+            callback(error, result);
         }
     };
 

dist/web3.js

@@ -2808,8 +2808,16 @@ HttpProvider.prototype.sendAsync = function (payload, callback) {
     var request = new XMLHttpRequest();
     request.onreadystatechange = function() {
         if (request.readyState === 4) {
-            // TODO: handle the error properly here!!!
-            callback(null, JSON.parse(request.responseText));
+            var result = request.responseText;
+            var error = null;
+
+            try {
+                result = JSON.parse(result);
+            } catch(e) {
+                error = errors.InvalidResponse(result);                
+            }
+
+            callback(error, result);
         }
     };
 

lib/web3/httpprovider.js

@@ -55,8 +55,16 @@ HttpProvider.prototype.sendAsync = function (payload, callback) {
     var request = new XMLHttpRequest();
     request.onreadystatechange = function() {
         if (request.readyState === 4) {
-            // TODO: handle the error properly here!!!
-            callback(null, JSON.parse(request.responseText));
+            var result = request.responseText;
+            var error = null;
+
+            try {
+                result = JSON.parse(result);
+            } catch(e) {
+                error = errors.InvalidResponse(result);                
+            }
+
+            callback(error, result);
         }
     };