javascript之Ajax获取和设置标头
XMLHttpRequest对象中与标头有关的方法:
setRequestHeader(<header>,<value>)——用指定值设置标头。
getResponseHeader(<header>)——获取指定标头的值;
getAllResponseHeaders()——以单个字符串形式获取全部标头。
覆盖请求的HTTP方法,例如以下代码:可规避防火墙仅仅同意GET和POST请求通过的限制;
httpRequest.setRequestHeader("X-HTTP-Method-Override","DELETE");禁用内容缓存:
httpRequest.setRequestHeader("Cache-Control","no-cache");
<!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>上海远地资产管理有限公司</title> <meta name="author" content="jason"/> <meta name="description" content="上海远地资产管理有限公司(简称:远地资产),是一家专业的互联网金融服务平台."/> <link rel="shortcut icon" href="images/favicon.ico" type="image/x-icon"/> <style type="text/css"> #allheaders,#ctheader{ border: medium solid black; padding: 2px; margin: 2px; } </style> </head> <body> <div> <button>Apples</button> <button>Cherries</button> <button>Bananas</button> </div> <div id="ctheader"></div> <div id="allheaders"></div> <div id="target"> 载入内容 </div> </table> <script> var buttons=document.getElementsByTagName("button"); for(var i=0;i<buttons.length;i++){ buttons[i].onclick=handleButtonPress; } var httpRequest; function handleButtonPress(e){ httpRequest=new XMLHttpRequest(); httpRequest.onreadystatechange=handleResponse; httpRequest.open("GET", e.target.innerHTML+".html"); //规避防火墙的限制,使用X-HTTP-Method-Override标头来指定想要的HTTP方法,但形式上市再发送一个POST请求 //httpRequest.setRequestHeader("X-HTTP-Method-Override","DELETE"); //禁用内容缓存 //httpRequest.setRequestHeader("Cache-Control","no-cache"); httpRequest.send(); } function handleResponse(){ if(httpRequest.readyState==2){ document.getElementById("allheaders").innerHTML=httpRequest.getAllResponseHeaders(); document.getElementById("ctheader").innerHTML=httpRequest.getResponseHeader("Content-Type"); }else if(httpRequest.readyState==4 && httpRequest.status==200){ document.getElementById("target").innerHTML= httpRequest.responseText; } } </script><pre name="code" class="html"></body> </html>