Why Does `myDiv.style.display` Return an Empty String When Set in a Master Stylesheet?

Patricia Arquette
Release: 2024-11-11 10:57:02
Original
630 people have browsed it

Why Does `myDiv.style.display` Return an Empty String When Set in a Master Stylesheet?

Master Stylesheet Effects on display Style

When displaying content using HTML's display style, it's essential to understand how inline and master stylesheets affect its behavior. This article explores the issue where myDiv.style.display returns an empty string when set in a master stylesheet, unlike when set inline.

Initial State of display

HTML elements typically start with a default display value, usually "inline". To override this, developers often use inline styles:

<div>
Copy after login

However, to increase maintainability, it's beneficial to set these initial styles in a master stylesheet.

Unexpected Behavior

When setting display:none in a master stylesheet, the initial state of the element remains hidden. However, accessing myDiv.style.display using JavaScript initially returns an empty string. This differs from inline styles, where it returns "none".

Resolved Issue Using getComputedStyle

The solution to this issue lies in understanding that accessing an element's CSS properties directly (e.g., element.style.display) retrieves their inline style settings. To access styles defined in external stylesheets or browser defaults, developers must use the getComputedStyle method:

function getStyle(id, name) {
    var element = document.getElementById(id);
    return element.currentStyle
        ? element.currentStyle[name]
        : window.getComputedStyle
        ? window.getComputedStyle(element, null).getPropertyValue(name)
        : null;
}

var display = getStyle('myDiv', 'display');
alert(display); // prints 'none' or 'block' or 'inline' etc.
Copy after login

By utilizing getComputedStyle, developers can accurately retrieve values set externally, including those in master stylesheets.

The above is the detailed content of Why Does `myDiv.style.display` Return an Empty String When Set in a Master Stylesheet?. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template