JavaScript - Auto Sum Value Base On Checkbox

In this tutorial we will create a Auto Sum Value Base On Checkbox using JavaScript. This code will automatically calculate the sum of the checkboxes value when user checked it. The code use onclick() to call a function that will auto sum the value of the checkboxes. You can apply this script to your code to make your transaction faster, it is a user-friendly program feel free to modify it. We will use JavaScript to add some new feature to the website interface by actually written into an HTML page. It is what gives your page a different interactive elements and animation that engage a user.

Getting Started:

This is the link for the bootstrap that i used for the layout design

The Main Interface

This code contains the interface of the application. To create this just write these block of code inside the text editor and save this as index.html.
  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4. <meta charset="UTF-8" name="viewport" content="width=device-width, initial-scale=1"/>
  5. <link rel="stylesheet" type="text/css" href="css/bootstrap.css" />
  6. </head>
  7. <nav class="navbar navbar-default">
  8. <div class="container-fluid">
  9. <a class="navbar-brand" href="">Sourcecodester</a>
  10. </div>
  11. </nav>
  12. <div class="col-md-3"></div>
  13. <div class="col-md-6 well">
  14. <h3 class="text-primary">JavaScript - Auto Sum Value Base On Checkbox</h3>
  15. <hr style="border-top:1px dotted #ccc;">
  16. <div class="col-md-4">
  17. <div class="form-group">
  18. <label><input type="checkbox" value="300" id="p1" onclick="UpdateCost(this);"> Milk, Price: 300</label>
  19. <label><input type="checkbox" value="150" id="p2" onclick="UpdateCost(this);"> Chocolate, Price: 150</label>
  20. <label><input type="checkbox" value="500" id="p3" onclick="UpdateCost(this);"> Wine, Price: 500</label>
  21. <label><input type="checkbox" value="100" id="p4" onclick="UpdateCost(this);"> Water, Price: 100</label>
  22. </div>
  23. </div>
  24. <div class="col-md-8">
  25. <div class="form-inline">
  26. <div class="form-inline">
  27. <label>Total Cost</label>
  28. <input type="text" id="total" disabled="disabled"/>
  29. </div>
  30. </div>
  31. </div>
  32. </div>
  33. <script src="js/script.js"></script>
  34. </body>
  35. </html>

Creating the Script

This code contains the script of the application. This code will auto sum the total value when the checkboxes is checked. To do this just copy and write these block of codes as shown below inside the text editor and save it as script.js inside the js directory
  1. var total=0;
  2. function UpdateCost(elem) {
  4. if (elem.checked == true) {
  5. total += Number(elem.value);
  6. }else{
  7. total -=Number(elem.value);
  8. }
  10. document.getElementById('total').value = total.toFixed(0);
  11. }
There you have it we successfully created a Auto Sum Value Base On Checkbox using JavaScript. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!

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