代碼如下var xhr=new XMLHttpRequest(); xhr.onreadystatechange=function(){???? if(xhr.readyState==4){???????? if((xhr.status>=200&&xhr.status<300)||xhr.status==304){???????????? alert(xhr.responseText)???????????? var myHeader=xhr.getResponseHeader("myHeader");???????????? console.log(myHeader)???????? }else{???????? ???? alert(xhr.status)???????? }???? } }; xhr.open("GET","a.txt",true); xhr.setRequestHeader("myHeader","myValue") xhr.send(null);