diff --git a/example/contract.html b/example/contract.html
index 44f0b03a19..403d8c9d19 100644
--- a/example/contract.html
+++ b/example/contract.html
@@ -50,7 +50,7 @@
 
     function callExampleContract() {
         // this should be generated by ethereum
-        var param = document.getElementById('value').value;
+        var param = parseInt(document.getElementById('value').value);
 
         // call the contract
         contract.multiply(param).call().then(function(res) {