JavaScript遮罩层

趁热打铁，又做了个遮罩层

var masking = {
    // opacity: float number between 0 and 1
    open : function(domIdStr, opacity){
        var mask = document.getElementById(domIdStr);
        mask.style.visibility = 'visiable';
        mask.style.position = 'absolute';
        mask.style.zIndex = '90';
        mask.style.left = '0';
        mask.style.top = '0';
        mask.style.width = '100%';
        mask.style.height = '100%';
        mask.style.backgroundColor = "#000";
        if(/msie/i.test(navigator.userAgent)){
            mask.style.filter = 'alpha(opacity=' + (opacity * 100) + ')';
        }else{
            mask.style.opacity = opacity;
        }
    },
    close : function(domIdStr){
        var mask = document.getElementById(domIdStr);
        mask.style.visibility = 'hidden';
    }
}

用法：在HTML页面</body>之前添加<div id="mask"></div>，调用open方法即可。