/**
 * AD Float Object
 * 
 * @desc:Create a float ad with image: ad.jpg
 * @example:FloatAd.newFloatAd("image_path/ad.jpg");
 * @desc:Create a float ad with image and url: ad.jpg
 * @example:FloatAd.newFloatAd("image_path/ad.jpg", "http://blog.csdn.net/xxd851116/");
 * 
 * @author: Xing,XiuDong :Last Editer
 * @date: 2009-09-17
 * @refers:	http://www.ahbofcom.gov.cn/js/FloatAd.js
 */
FloatAd = { 
    "ads" : new Object,
    /**
     * @param imgUrl : image path
     * @param strLink : image link address
     * @param top : image top at starting..
     * @param left : image left at starting..
     */
    "newFloatAd" : function(imgUrl, strLink, top, left) {
        var ad = document.createElement("a"); 
        ad.DirV = true; 
        ad.DirH = true; 
        ad.AutoMove = true; 
        ad.Image = new Image; 
        ad.Seed = Math.random(); 
        ad.Timer = setInterval("FloatAd.float(" + ad.Seed + ")", 20); 
        this.ads[ad.Seed] = ad; 
        ad.Image.Parent = ad; 
        ad.style.position = "absolute"; 
        ad.style.left = left || 0; 
        ad.style.top = top || 0; 
        ad.Image.src = imgUrl; 
        ad.Image.onmouseover = function(){this.Parent.AutoMove = false;};
        ad.Image.onmouseout = function(){this.Parent.AutoMove = true;};
        if(strLink) { 
            ad.href = strLink; 
            ad.Image.border = 0; 
            ad.target = "_blank"; 
        } 
        ad.appendChild(ad.Image); 
        document.body.appendChild(ad); 
        return ad; 
    }, 
    "float" : function(floatId){ 
        var ad = this.ads[floatId]; 
        if(ad.AutoMove){ 
            var curLeft = parseInt(ad.style.left); 
            var curTop = parseInt(ad.style.top); 
            if(ad.offsetWidth + curLeft > document.documentElement.clientWidth + document.documentElement.scrollLeft - 1){ 
                curLeft = document.documentElement.scrollLeft + document.documentElement.clientWidth - ad.offsetWidth; 
                ad.DirH = false; 
            } 
            if(ad.offsetHeight + curTop > document.documentElement.clientHeight + document.documentElement.scrollTop - 1){ 
                curTop = document.documentElement.scrollTop + document.documentElement.clientHeight - ad.offsetHeight; 
                ad.DirV = false; 
            } 
            if(curLeft < document.documentElement.scrollLeft) { 
                curLeft = document.documentElement.scrollLeft; 
                ad.DirH = true; 
            } 
            if(curTop < document.documentElement.scrollTop) { 
                curTop = document.documentElement.scrollTop; 
                ad.DirV = true; 
            } 
            ad.style.left = curLeft + (ad.DirH ? 1 : -1) + "px";
            ad.style.top = curTop + (ad.DirV ? 1 : -1) + "px";
        }
    }
};