<script type="text/javascript">
	/*判断可显示区域高度 用于决定显示主图的高度 这里高度比例和内容页不同*/
    var getBgHeight = function(windowHeight, bannerHeight, mobileBannerHeight){
        windowHeight = windowHeight || 560;
        if (windowHeight > window.screen.availHeight) {
            windowHeight = window.screen.availHeight;
        }
        bannerHeight = bannerHeight.trim();
        mobileBannerHeight = mobileBannerHeight.trim();
        if (window.innerHeight > window.innerWidth) {
            bannerHeight = parseFloat(mobileBannerHeight);
        } else {
            bannerHeight = parseFloat(bannerHeight);
        }
        bannerHeight = Math.round(windowHeight * bannerHeight / 100);
        return bannerHeight;
    };
        var head = $("#masthead");
        var bgHeight = getBgHeight(window.innerHeight, '35', '25');
        head.css('height', bgHeight + "px");
</script>