function getYesterday(date) { var date = date.split('-'), today = new Date().setFullYear(+date[0], +date[1]-1, +date[2]), yesterday = new Date(today - 24 * 60 * 60 * 1000); var y = yesterday.getFullYear(); var m = yesterday.getMonth() + 1; var d = yesterday.getDate(); if(m<10){ m = '0'+m; } if(d<10){ d = '0'+d; } return y+''+m+''+d; } getYesterday("20140421");