Use the correct event handler

Oct 13, 2025 by talynt.org 1 views

Introduction

When it comes to loading external scripts in HTML, developers often rely on setTimeout to ensure that the script is loaded before executing any code. However, this approach can lead to errors and inconsistencies, especially in modern web development. In this article, we will explore the benefits of replacing setTimeout with onLoad and provide a step-by-step guide on how to update example code to use the latter.

Understanding the Problem with setTimeout

setTimeout is a function that allows you to execute a piece of code after a specified delay. In the context of loading external scripts, it is often used to wait for the script to load before executing any code. However, this approach has several drawbacks:

Inconsistent behavior: setTimeout relies on the browser's timing and scheduling, which can lead to inconsistent behavior across different browsers and devices.
Error-prone: If the script fails to load or takes longer than expected, the code executed after setTimeout may not work as intended.
Security risks: Using setTimeout can create security vulnerabilities if the code executed after the delay is not properly sanitized.

Introducing onLoad

onLoad is a more reliable and efficient way to load external scripts. It allows you to execute code only when the script has finished loading, eliminating the need for setTimeout. In modern web development, onLoad is the preferred approach for loading external scripts.

Updating Example Code

Let's take a look at the example code provided:

<!-- START Formbricks Surveys -->
<script type="text/javascript">
!function() {
var t = document.createElement("script");
t.type = "text/javascript";
t.async = true;
t.src = "https://app.formbricks.com/js/formbricks.umd.cjs";
t.**onload** = function() {
if (typeof window.formbricks !== 'undefined' && typeof window.formbricks.init === 'function') {
window.formbricks.init({
environmentId: "ENVID",
apiHost: "https://app.formbricks.com/"
});
} else {
console.error('formbricks.init is not defined');
}
};

var e = document.getElementsByTagName("script")[0];
e.parentNode.insertBefore(t, e);
}();

</script>
<!-- END Formbricks Surveys -->

In this code, we can see that onLoad is already being used to load the formbricks.umd.cjs script. However, to update the code to use onLoad consistently, we need to make a few changes.

Step 1: Remove setTimeout

The first step is to remove the setTimeout function from the code. Since onLoad is already being used, we can simply remove the setTimeout function and its associated code.

Step 2: Update the Code to Use onLoad

After removing setTimeout, we need to update the code to use onLoad consistently. We can do this by adding the onLoad event handler to the script element.

Updated Code

Here is the updated code:

<!-- START Formbricks Surveys -->
<script type="text/javascript">
!function() {
var t = document.createElement("script");
t.type = "text/javascript";
t.async = true;
t.src = "https://app.formbricks.com/js/formbricks.umd.cjs";
t.**onload** = function() {
if (typeof window.formbricks !== 'undefined' && typeof window.formbricks.init === 'function') {
window.formbricks.init({
environmentId: "ENVID",
apiHost: "https://app.formbricks.com/"
});
} else {
console.error('formbricks.init is not defined');
}
};

var e = document.getElementsByTagName("script")[0];
e.parentNode.insertBefore(t, e);
}();

</script>
<!-- END Formbricks Surveys -->

Conclusion

Replacing setTimeout with onLoad is a simple yet effective way to improve the reliability and efficiency of loading external scripts. By using onLoad, we can ensure that code is executed only when the script has finished loading, eliminating the need for setTimeout. In this article, we provided a step-by-step guide on how to update example code to use onLoad consistently.

Best Practices for Using onLoad

When using onLoad, it's essential to follow best practices to ensure that code is executed correctly:

Use the correct event handler: Make sure to use the onLoad event handler instead of onreadystatechange or onload (without the capital "L").
Check for script loading: Always check if the script has finished loading before executing code.
Handle errors: Use try-catch blocks to handle errors that may occur during script loading.

Updating Documentation and Configuration

To ensure that the updated code is used consistently across the application, it's essential to update documentation and configuration files. This includes:

Updating documentation: Update documentation to reflect the use of onLoad instead of setTimeout.
Updating configuration files: Update configuration files to use onLoad consistently.

Onboarding and Training

To ensure that developers understand the benefits of using onLoad and how to update code to use it consistently, it's essential to provide onboarding and training:

Provide training: Provide training sessions to developers on the benefits of using onLoad and how to update code to use it consistently.
Update onboarding process: Update the onboarding process to include information on using onLoad consistently.

Conclusion

Introduction

Replacing setTimeout with onLoad is a simple yet effective way to improve the reliability and efficiency of loading external scripts. However, there may be questions and concerns about how to implement this change. In this article, we will provide a Q&A guide to help you understand the benefits and best practices of using onLoad consistently.

Q1: What is the main difference between setTimeout and onLoad?

A1: The main difference between setTimeout and onLoad is that setTimeout executes code after a specified delay, whereas onLoad executes code only when the script has finished loading.

Q2: Why should I replace setTimeout with onLoad?

A2: You should replace setTimeout with onLoad because it provides a more reliable and efficient way to load external scripts. onLoad eliminates the need for setTimeout and ensures that code is executed only when the script has finished loading.

Q3: How do I update my code to use onLoad consistently?

A3: To update your code to use onLoad consistently, you need to:

Remove setTimeout from your code
Add the onLoad event handler to the script element
Check if the script has finished loading before executing code

Q4: What are the best practices for using onLoad?

A4: The best practices for using onLoad are:

Use the correct event handler (onLoad instead of onreadystatechange or onload without the capital "L")
Check if the script has finished loading before executing code
Handle errors that may occur during script loading

Q5: How do I update my documentation and configuration files to reflect the use of onLoad?

A5: To update your documentation and configuration files to reflect the use of onLoad, you need to:

Update documentation to reflect the use of onLoad instead of setTimeout
Update configuration files to use onLoad consistently

Q6: What is the onboarding and training process for using onLoad consistently?

A6: The onboarding and training process for using onLoad consistently includes:

Providing training sessions to developers on the benefits of using onLoad and how to update code to use it consistently
Updating the onboarding process to include information on using onLoad consistently

Q7: What are the benefits of using onLoad consistently?

A7: The benefits of using onLoad consistently are:

Improved reliability and efficiency of loading external scripts
Elimination of the need for setTimeout
Better handling of errors that may occur during script loading

Q8: How do I troubleshoot issues related to onLoad?

A8: To troubleshoot issues related to onLoad, you need to:

Check if the script has finished loading before executing code
Handle errors that may occur during script loading
Use debugging tools to identify and fix issues related to onLoad

Q9: Can I use both setTimeout and onLoad in my code?

A9: No, you should not use both setTimeout and onLoad in your code. onLoad is a more reliable and efficient way to load external scripts, and using both setTimeout and onLoad can lead to inconsistent behavior.

Q10: What are the future plans for using onLoad consistently?

A10: The future plans for using onLoad consistently include:

Continuing to provide training and onboarding sessions to developers on the benefits of using onLoad and how to update code to use it consistently
Updating documentation and configuration files to reflect the use of onLoad consistently
Exploring new features and best practices for using onLoad consistently

Conclusion

Replacing setTimeout with onLoad is a simple yet effective way to improve the reliability and efficiency of loading external scripts. By using onLoad consistently, you can eliminate the need for setTimeout and ensure that code is executed only when the script has finished loading. In this article, we provided a Q&A guide to help you understand the benefits and best practices of using onLoad consistently.