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JavaScript JavaScript and the DOM (Retiring) Making Changes to the DOM Styling Elements

Posted by Nuriddin Ikramov
Nuriddin Ikramov
5,866 Points

The code explanation

I have two questions: 1) Could you explain the conditional statement? I dont understand why I should use if(listDiv.style.display=='none'), as the default value of display is 'block'? Why does it enter the first statement?

2 Answers

Aled Bidder
Aled Bidder
7,863 Points
Aled Bidder
Aled Bidder
7,863 Points

I was confused about this until I remembered that the conditional statement runs on the click of the button.

At that point the function checks the display style of the div.

The first time you click it, the display is set to an empty string (''), and so it runs the else statement and changes the display to 'none' and thus hides the div.

If you then click the button again, the display is set to 'none' and so the function runs the first part of the statement and changes the display to 'block' and thus shows the div again.

Finally working this out has been a huge relief! I hope it helps you too 👍

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The default value of style.display is not "block", it's simply an empty string ("").

For some elements (for example, "div") the default display mode is block, but that default is overridden when something is assigned directly to the style.display attribute.