I have the following contract (Test.sol):

contract Test {

bytes32 message = "This is a message.";

function setMessage(bytes32 _message) {
    message = _message;

function getMessage() constant returns (bytes32) {
    return message;

function stringToBytes32(string memory source) returns (bytes32 result) {
    assembly {
result := mload(add(source, 32))

I am trying to make an app where the user enters text and clicks a button, then the setMessage() and getMessage() functions are executed, and the message is displayed.

My index.html file (straightforward):

<input type="text" id="textbox" placeholder="enter something">
<a href="#" onclick="setMessage()" class="btn btn-primary">Submit</a>
<div id="displayedMessage"></div>

and the app.js file that index.html refers to:

  window.setMessage = function () {
  let message = $('#textbox').val()

  Test.deployed().then(function (contractInstance) {
    contractInstance.setMessage(stringToBytes32(message), { gas: 140000, from: web3.eth.accounts[0] }).then(function () {
      contractInstance.getMessage().then(function (v) {


There is something wrong with the above code in app.js as the setMessage() function doesn't get called at all, though I don't know why not (I'm not getting any errors in the browser or truffle console). Or maybe it's an issue with converting the string to bytes32. The contract is deployed properly - if instead of the above, I have something like the following:

window.setMessage = function () {
Test.deployed().then(function(contractInstance) {
        contractInstance.getMessage().then(function(v) {

Then getMessage() gets called. But I can't seem to call setMessage()

1 Answer 1


The problem is that you are calling stringToBytes32(message) in line:

contractInstance.setMessage(stringToBytes32(message), { gas: 140000, from: web3.eth.accounts[0] }).then(function () {

as it was a local javascript function while it's a contract method and it should be invoked in a similar way you are invoking setMessage or be called inside the contract context.

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