新手求教 json问题

m_star_moon 2019-03-16 12:02:43

<!doctype html>

<html>

 <head>

  <meta charset="UTF-8">

  <title>Document</title>

  <script src="js/common.js"></script>

  <script>

	function loadProvince(){

		//获取xhr

		var xhr=createXhr();

		//创建请求

		xhr.open("get","php/province2.php",true);

		//设置回调函数

		xhr.onreadystatechange=function(){

			if(xhr.readyState==4&&xhr.status==200){

				var resText=JSON.parse(xhr.responseText);

				console.log(resText);

                var html="";

				for(var i=0;i<resText.length;i++){

					html+="<option value=";

					html+=i;

					html+=">";

					html+=resText[i];

					html+="</option>";

				}

				console.log(html);

				$("selProvince").innerHTML=html;

			}

		}

		//发送请求

		xhr.send(null);

	}

  </script>

  <script>

	function loadCity(){

		//获取xhr

		var xhr=createXhr();

		//创建请求

		var pid=$("selProvince").value;

		var url="php/province3.php?pid="+pid;

		xhr.open("get","php/province3.php?pid="+pid,true);

		//设置回调函数

		xhr.onreadystatechange=function(){

			if(xhr.readyState==4&&xhr.status==200){

				console.log(xhr.responseText);//为什么xhr.responseText()接收不到json字符串？？？我哪里有问题

				var opts=JSON.parse(xhr.responseText);

				var html="";

				for(var i=0;i<opts.length;i++){

					html+="<option value=";

					html+=i;

					html+=">";

					html+=opts[i];

					html+="</option>";

				}

				$("selCity").innerHTML=html;

			}

		}

		//发送请求

		xhr.send(null);

	}

  </script>

  <script>

	function onloadPrev(){

		loadProvince();

		loadCity();

	}

  </script>

 </head>

 <body onload="onloadPrev()">

	<select id="selProvince"></select> 

	<select id="selCity"></select>

 </body>

</html>

<?php

    header("Content-Type:application/json");

	$province=["黑龙江","吉林","辽宁"];

	echo json_encode($province);

?>

<?php

	header("Content-Type:application/json");

	$city=[

	["黑河","哈尔滨","五常市"],

	["长春","四平市","松原市"],

	["沈阳","大连市","抚顺市"]

	];

	$value=$_REQUEST["pid"];

	//var_dump($city);

	echo json_encode($city[$value]);

?>

...全文