var winheight = $(window).height();
示例:返回顶部功能实现
//返回顶部 $(window).scroll(function() { var top=jQuery(document).scrollTop(); var winheight = $(window).height(); if(top>winheight){ $('.backtotop').css('display','block'); }else{ $('.backtotop').css('display','none'); } }); $('.backtotop').click(function(){ $('html, body').animate({scrollTop:0},'fast'); });