Скачать или смотреть How to Fix String is Empty on Submit Error in JavaScript Forms

Learn how to correctly retrieve user input values in JavaScript forms. This guide explains the issue of an empty string on form submission and provides a quick fix.
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This video is based on the question https://stackoverflow.com/q/62520108/ asked by the user 'Sackadelic' ( https://stackoverflow.com/u/10908002/ ) and on the answer https://stackoverflow.com/a/62520227/ provided by the user 'Barmar' ( https://stackoverflow.com/u/1491895/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting the String is Empty on Submit Error in JavaScript Forms

When working on web forms, you might encounter scenarios where user input is not being captured correctly. A common issue is when attempting to retrieve a value from a form input, only to find that it is empty upon submission. This post delves into the problem faced by a user attempting to get a number from user input and provides an effective solution.

The Problem: Capturing User Input in Forms

In a recent coding exercise, a user found themselves unable to retrieve a number inputted by the user in an HTML form. They intended for the user to select a number between 1 and 10, after which they would receive an alert if their guess matched a randomly generated number. Despite trying various approaches, they struggled to log the user's input to the console successfully. Here's what their initial setup looked like:

Initial Code Snippet

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The Flaw in the Setup

In the code above, the issue arises because the input variable is assigned the value of the input field when the page loads. Therefore, when the button is clicked, it logs the original (and potentially empty) value, rather than the current value that the user has entered.

The Solution: Capture Input on Click

To fix this problem, we need to ensure that we capture the input value when the button is clicked. This involves moving the retrieval of the input value inside the button's onclick function. Here's how you can adjust the code accordingly.

Updated Code Snippet

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What Changed?

Input Value Retrieval: The input variable is now declared inside the button's onclick function. This ensures it fetches the current user input whenever the button is clicked.

Logging Both Values: The code now logs both the randomly generated number and the user's input for better debugging.

Complete HTML Example for Context

To provide full context, here's how the HTML part of the form should look:

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Conclusion

By adjusting where and how you retrieve the input value, you can effectively resolve the string is empty on submit issue. This small change can significantly improve user interaction with your forms, allowing for successful value capture and processing. Happy coding!