Reduce the burden of JavaScript testing and debugging

Web development platforms like JSP, ASP.NET, ColdFusion provide a large number of powerful server-side development options. However, they do not negate client-side web development with JavaScript.

JavaScript provides both logic and user interface functions, reducing the load of server-side processing. Even though we've been using it for years, its development tools are a bit behind the times. Now let's take a closer look at JavaScript development and debugging options.

Development Tools

If you are used to using an integrated development environment (IDE) such as Visual Studio or NetBeans, then you must be familiar with various debugging options, including code stepping, setting breakpoints, and monitoring variables. These are indispensable tools when monitoring code execution or tracking down bugs. Unfortunately, these tools are not very popular among JavaScript developers.

Debugging

An important step in application development is tracking down errors in scripts or code. This involves isolating code snippets and analyzing them line by line. When using JavaScript, you can use methods that were used before the development of development tools.

In this case, one of the most commonly used JavaScript functions is the alert message box. You can use it to examine the value stored in a variable/object, and use it with loops to view the contents of the object.

For example, the HTML code in List A does not execute as expected:

function validate() {
var doc = document.forms[0];
var flag = true;
if (doc.fullName.value = '')
flag = false;
if (doc.contactNumber.value = '')
flag = false;
if (flag) doc.submit()
else alert('Enter values ​​before submitting.');
}

Name:

Address:

> ;

It stands to reason that it will validate the values ​​entered in the two text fields before the form is actually submitted.

This form is always submitted regardless of the value entered, so we can use an alert statement to check the contents of the value during script execution. The script in Listing B uses an alert statement to monitor the value of a variable:

Name:

Address:

> ;

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