Changing HTML using execute command not working

[dharls36]

Ok, so I'm trying to change the page title for testing purposes but cannot seem to get it to work.

Firstly, here is my HTML for the page title;

and here is my nightwatch test script for changing the page title, adapted from the nightwatch documentation

browser.execute(function(document) {
	document.getElementByClassName('main-heading__title').innerHTML = 'Doc title = ' + document.title;
	return true;
	}, [ ], function(result) {
});

However, when I run this, I get the following error;

Error while running .executeScript() protocol action: An error occurred while executing user supplied JavaScript. – javascript error: Cannot read properties of undefined (rea...

I also get the same error if I try and located the element, as such;

browser.execute(function(document) {
	document.getElementByClassName('main-heading__title');
	return true;
	}, [ ], function(result) {
});

Am I doing something obviously wrong with either my javascript, nightwatch syntax, or both?

Any help would be greatly appreciated. Thanks.

[beatfactor]

Just remove the document from the function arguments that you're trying to execute. E.g.:

browser.execute(function() {
  return document.getElementByClassName('main-heading__title');
}, [
 // args to be passed to the function executed in the browser context
], function callback(result) {
  console.log('Result from execute', result);
})

[dharls36]

Many thanks for the reply @beatfactor

Ok, so I've amended my code to look like this;

browser.url(browser.launch_url);
browser.pause(5000);
browser.execute(function() {
	document.getElementByClassName('main-heading__title').innerHTML = 'Doc title = ' + document.title;
}, [
 ], function callback(result) {
	console.log('Result from execute', result);
});

However, when I run the test I get a different error;

Error while running .executeScript() protocol action: An error occurred while executing user supplied JavaScript. – javascript error: document.getElementByClassName is not a ...

Result from execute {
  status: -1,
  state: '',
  code: '',
  value: {
    message: 'javascript error: document.getElementByClassName is not a function',
    error: [
      '  (Session info: chrome=95.0.4638.69)',
      '  (Driver info: chromedriver=95.0.4638.54 (d31a821ec901f68d0d34ccdbaea45b4c86ce543e-refs/branch-heads/4638@{#871}),platform=Mac OS X 11.6.1 x86_64)'
    ]
  },
  errorStatus: 17,
  error: 'An error occurred while executing user supplied JavaScript. – javascript error: document.getElementByClassName is not a ...',
  httpStatusCode: 200
}

This is the first time I've used the execute command, so apologies if I'm doing something obviously wrong with this.

Thanks.

[dharls36]

p.s. I also tried document.getElementsByClassName with same results. Thanks.

[beatfactor]

Well, the error is there for you: javascript error: document.getElementByClassName is not a function.