How to Access HTML Element Style Values in JavaScript Without Using Libraries?

Accessing HTML Element Style Values in JavaScript without Libraries

Introduction:

Manipulating an HTML element's style attributes is a crucial aspect of dynamic web applications. This question explores how to retrieve style values from an element that has styles set through the

Retrieving Style Values:

To retrieve the inline styles defined using the

Cross-Browser Approach:

Getting computed styles cross-browser can be tricky. Internet Explorer (IE) has its own mechanism, element.currentStyle, while other browsers use the document.defaultView.getComputedStyle method.

Cross-Browser Function:

To simplify this cross-browser implementation, a function called getStyle() can be defined:

function getStyle(el, styleProp) {
  var value, defaultView = (el.ownerDocument || document).defaultView;
  if (defaultView && defaultView.getComputedStyle) {
    styleProp = styleProp.replace(/([A-Z])/g, "-").toLowerCase();
    return defaultView.getComputedStyle(el, null).getPropertyValue(styleProp);
  } else if (el.currentStyle) {
    styleProp = styleProp.replace(/\-(\w)/g, function(str, letter) {
      return letter.toUpperCase();
    });
    value = el.currentStyle[styleProp];
    if (/^\d+(em|pt|%|ex)?$/i.test(value)) { 
      return convertIEValueToPixels(value);
    }
    return value;
  }
}

This function sanitizes the property name for cross-browser compatibility and handles unit conversion on IE.

Usage:

To retrieve a specific style property, use the getStyle() function with the desired property name, such as:

var width = getStyle(document.getElementById("box"), "width");

Limitations:

The getStyle() function provides a useful cross-browser approach. However, it has limitations, particularly in handling certain properties, such as colors, where IE may return the defined value instead of the computed value. For example, a color property defined as #ff0000 might return red upon calling getStyle().

The above is the detailed content of How to Access HTML Element Style Values in JavaScript Without Using Libraries?. For more information, please follow other related articles on the PHP Chinese website!