Getting URL parameters with JavaScript

To write JavaScript code to parse URL parameters, you can use the built-in URLSearchParams API. This API allows you to work with the query string of a URL easily. Here's a simple function to parse URL parameters and return an object containing the key-value pairs:

function getUrlParameters() {
  const urlParams = new URLSearchParams(window.location.search);
  const params = {};

  for (const [key, value] of urlParams.entries()) {
    params[key] = value;
  }

  return params;
}

You can use this function to get an object containing the URL parameters as key-value pairs. Here's an example of how to use this function:

const params = getUrlParameters();
console.log(params);

// If the URL is "https://example.com?prolificPID=12345&studyID=67890&sessionID=abcde", the output will be:
// {
//   prolificPID: "12345",
//   studyID: "67890",
//   sessionID: "abcde"
// }

The getUrlParameters() function works as follows:

It creates a new instance of URLSearchParams using the window.location.search property, which contains the query string of the current URL, including the leading question mark (?).
It initializes an empty object named params to store the key-value pairs.
It iterates over the entries of the urlParams object using a for-of loop.
For each key-value pair, it adds the pair to the params object.
It returns the params object containing the parsed URL parameters.

This function can be used to easily access the URL parameters in your JavaScript code. Note that this code assumes the browser supports the URLSearchParams API, which is widely supported in modern browsers.

Redirects

In online studies on prolific, participants need to be sent back to prolific after completing a study.

To redirect participants back to Prolific using JavaScript, you can use the window.location.replace() method. This method replaces the current document with a new one, and the new URL will not be saved in the browser's history, meaning the user cannot use the "Back" button to navigate back to the previous page. This is useful in cases like completing a study, where you don't want users to return to the survey accidentally.

Here's an example of how to use window.location.replace() to redirect users back to Prolific using the URL that is provided by Prolific:

function redirectToProlific() {
  const prolificCompletionUrl = 'https://app.prolific.co/submissions/complete?cc=C7ZNXQ0L';
  window.location.replace(prolificCompletionUrl);
}

You can call this redirectToProlific() function when you want to redirect participants back to Prolific, for example, after they have completed the survey or met the necessary requirements:

// Call the redirectToProlific function when appropriate, e.g., on successful survey submission
redirectToProlific();

When the redirectToProlific() function is called, the browser will navigate to the specified Prolific completion URL, allowing participants to complete their submission and receive payment for their work.