精通JavaScript源码3

ruisheng_412

于 2009-03-22 15:49:33 发布

阅读量138

点赞数

分类专栏： JAVASCRIPT 文章标签： JavaScript IE ViewUI

JAVASCRIPT 专栏收录该内容

9 篇文章

订阅专栏

本文介绍了通过JavaScript来实现网页元素的隐藏与显示，以及如何调整元素的透明度。提供了两个实用函数，分别是用于隐藏元素的`hide`函数和显示元素的`show`函数，并且给出了一种设置元素透明度的方法。

设置元素的隐藏或者可见：

// A function for hiding (using display) an element
function hide( elem ) {
    // Find out what it’s current display state is
    var curDisplay = getStyle( elem, ‘display’ );
    //  Remember its display state for later
    if ( curDisplay != ‘none’ )
        elem.$oldDisplay = curDisplay;
    // Set the display to none (hiding the element)
    elem.style.display = ‘none’;
}
// A function for showing (using display) an element
function show( elem ) {
    // Set the display property back to what it use to be, or use
    // ‘block’, if no previous display had been saved
    elem.style.display = elem.$oldDisplay || ‘block’;
}

设置元素的透明度：

// Set an opacity level for an element
// (where level is a number 0-100)
function setOpacity( elem, level ) {
    // If filters exist, then this is IE, so set the Alpha filter
    if ( elem.filters )
        elem.filters.alpha.opacity = level;

    // Otherwise use the W3C opacity property
    else
        elem.style.opacity = level / 100;
}