常用header汇总：

header('Content-Type: text/html; charset=utf-8'); //网页编码

header('Content-Type: text/plain'); //纯文本格式

header('Content-Type: image/jpeg'); //JPG、JPEG

header('Content-Type: application/x-www.form-urlencoded'); //表单提交格式

header('Content-Type: application/zip'); // ZIP文件

header('Content-Type: application/pdf'); // PDF文件

header('Content-Type: audio/mpeg'); // 音频文件

header('Content-type: text/css'); //css文件

header('Content-type: text/javascript'); //js文件

header('Content-type: application/json'); //json

header('Content-type: application/pdf'); //pdf

header('Content-type: text/xml'); //xml

header('Content-Type: application/x-shockw**e-flash'); //Flash动画