遮罩层

/**
 * 给元素增加遮罩层
 * @param maskLayer 遮罩层
 * @param maskObj 被遮罩元素
 */
function doMask(maskLayer,maskObj){
    maskLayer.css("filter","alpha(opacity=60)");
    maskLayer.css("background-color","#777");
    maskLayer.css("z-index","1002");
    maskLayer.css("opacity","0.5");
    maskLayer.css("-moz-opacity","0.5");
    maskLayer.css("position","absolute");
    maskLayer.css("width",maskObj.width());
    maskLayer.css("height",maskObj.height());
    maskLayer.css("left",maskObj.position().left+1);
    maskLayer.css("top",maskObj.position().top+1);
}