javascript - php檔案中執行print_r($_POST)時，顯示Array()，為什麼呢？

 function createXML(){                var xml = "";                var options = document.getElementById("petTypes").childNodes;                var option = null;                for(var i = 0;i < options.length;i++){                    option = options[i];                    if(option.selected){                        xml = xml + "" + option.value + "<\/type>";                    }                }                xml = xml + "<\/pets>";                return xml;            }                        function sendPetTypes(){                createXMLHttpRequest();                var xml = createXML();                var url = "PostingXMLExample.php?timeStamp=" + new Date().getTime();                                xmlHttp.open("POST",url,true);                xmlHttp.onreadystatechange = handleStateChange;                xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded;");                xmlHttp.send(xml);            }

php檔案中執行print_r($_POST)時，顯示Array()，當執行echo file_get_contents("php://input")時，顯示內容，為什麼呢？請大神賜教

function handleStateChange(){                if(xmlHttp.readyState == 4){                    if(xmlHttp.status == 200){                        parseResults();                    }                }            }                        function parseResults(){                var responseDiv = document.getElementById("serverResponse");                if(responseDiv.hasChildNodes()){                    responseDiv.removeChild(responseDiv.childNodes[0]);                }                var responseText = document.createTextNode(xmlHttp.responseText);                responseDiv.appendChild(responseText);            }

回複內容：

 function createXML(){                var xml = "";                var options = document.getElementById("petTypes").childNodes;                var option = null;                for(var i = 0;i < options.length;i++){                    option = options[i];                    if(option.selected){                        xml = xml + "" + option.value + "<\/type>";                    }                }                xml = xml + "<\/pets>";                return xml;            }                        function sendPetTypes(){                createXMLHttpRequest();                var xml = createXML();                var url = "PostingXMLExample.php?timeStamp=" + new Date().getTime();                                xmlHttp.open("POST",url,true);                xmlHttp.onreadystatechange = handleStateChange;                xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded;");                xmlHttp.send(xml);            }

php檔案中執行print_r($_POST)時，顯示Array()，當執行echo file_get_contents("php://input")時，顯示內容，為什麼呢？請大神賜教

function handleStateChange(){                if(xmlHttp.readyState == 4){                    if(xmlHttp.status == 200){                        parseResults();                    }                }            }                        function parseResults(){                var responseDiv = document.getElementById("serverResponse");                if(responseDiv.hasChildNodes()){                    responseDiv.removeChild(responseDiv.childNodes[0]);                }                var responseText = document.createTextNode(xmlHttp.responseText);                responseDiv.appendChild(responseText);            }

 xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 

看著好像是多了個; ???

因為在傳遞過來的時候，傳遞的是字串，這個時候PHP幫你自動轉成了數組，但是後面get_file_contents(php://input)這個是讀取的未經處理資料流，這個時候就需要你自己進行轉了。

