《精通javascript》几个简单的函数(二)

/**
* 隐藏元素
* @param {String} elem
*/
function hide(elem){
var curDisplay = getStyle(elem, 'display');
if(curDisplay != 'none'){
        elem.oldDisplay = curDisplay;
    }
    elem.style.display = 'none';
}
/**
* 显示元素
* @param {String} elem
*/
function show(elem){
    elem.style.display = elem.oldDisply || 'block';
}
/**
* 设置透明度
* @param {Object} elem
* @param {Object} level (0-100)
*/
function setOpacity(elem, level){
if(elem.filters){ //如果是IE
        elem.style.filter = 'alpha(opacity=' + level + ')';
//必须设置zoom,要不然透明度在IE下不生效  From:http://blog.csdn.net/dxx1988/article/details/6581430
        elem.style.zoom = 1;
    } else { //否则是W3C
        elem.style.opacity = level / 100;
    }
}
/**
* 滑动
* @param {Object} elem
*/
function slideDown(elem){
//elem.style.height = '0px';
    show(elem);
var h = fullHeight(elem);
for(var i=0; i<=100; i+=5){
        (function(){
var pos = i;
            setTimeout(function(){
                elem.style.height = (pos/100) * h + 'px';
            }, (pos + 1) * 5);
        })();
    }
}
//slideDown($('pText'));
//alert(fullHeight($('pText')));
/**
* 透明度渐显 From: http://mrthink.net/js-fadein-fadeout-fadeto/
* @param {Object} elem
* @param {Number} speed 淡入速度,正整数(可选)
* @param {Number} opacity 淡入到指定的透明度,0~100(可选)
*/
function fadeInThink(elem, speed, opacity){
    speed = speed || 20;
    opacity = opacity || 100;
    show(elem);
    setOpacity(elem, 0);
//初始化透明度变化值为0
var val = 0;
//循环将透明值以5递增,即淡入效果
    (function(){
        setOpacity(elem, val);
        val += 5;
if (val <= opacity) {
            setTimeout(arguments.callee, speed)
        }
    })();
}
/**
* 透明度渐显
* @param {Object} elem
*/
function fadeIn(elem){
//setOpacity(emel, 0);
    show(elem);
for(var i=0; i<=100; i+=10){
        (function(){
var pos = i;
            setTimeout(function(){
                setOpacity(elem, pos);
            }, (pos + 1) * 10);
        })();
    }
}
/**
* 透明度渐隐 From: http://mrthink.net/js-fadein-fadeout-fadeto/
* @param {Object} elem
*/
function fadeOut(elem){
var val = 100;
    (function(){
        setOpacity(elem, val);
        val -= 5;
if(val >= 0){
            setTimeout(arguments.callee, 50);
        } else if(val < 0){
            hide(elem);
        }
    })();
}
//fadeInThink($('pText'));
/**
* 光标的水平位置
* @param {Object} e
*/
function getX(e){
    e = e || window.event;
return e.pageX || e.clientX + document.body.scrollLeft;
}
/**
* 光标的垂直位置
* @param {Object} e
*/
function getY(e){
    e = e || window.event;
return e.pageY || e.clientY + document.body.scrollTop;
}
/**
* 获得鼠标相对于当前元素的X位置
* @param {Object} e
*/
function getElementX(e){
return (e && e.layerX) || window.event.offsetX;
}
/**
* 获得鼠标相对于当前元素的Y位置
* @param {Object} e
*/
function getElementY(e){
return (e && e.layerY) || window.event.offsetY;
}
/**
* 当前页面的高度
*/
function pageHeight(){
return document.body.scrollHeight;
}
/**
* 当前页面的宽度
*/
function pageWidth(){
return document.body.scrollWidth;
}
//alert(pageHeight());
/**
* 视口的高度
*/
function windowHeight(){
var de = document.documentElement;
return self.innerHeight || (de && de.clientHeight) || document.body.clientHeight;
}
/**
* 视口的高度
*/
function windowWidth(){
var de = document.documentElement;
return self.innerWidth || (de && de.clientWidth) || document.body.clientWidth;
}
/**
* 浏览器水平滚动位置
*/
function scrollX(){
var de = document.documentElement;
return self.pageOffsetset ||  (de && de.scrollLeft) || document.body.scrollLeft;
}
/**
* 浏览器垂直滚动位置
*/
function scrollY(){
var de = document.documentElement;
return self.pageYOffset || (de && de.scrollTop) || document.body.scrollTop;
}