data.txt
{
"number1":1200,
}
index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
大盘指数：<span id="number" style="color: red;font-size: 36px;">1000</span>
<script src="../js/jquery.js"></script>
<script>
$(function() {
//每隔1000毫秒，发出一次ajax请求，响应数据
setInterval(function(){
$.getJSON('data.txt',function(data) {
$('#number').text(data.number1);
});
},1000);
});
</script>
</body>
</html>
wh_data.txt
[
{"id":"1","tagName":"apple"},
{"id":"2","tagName":"orange"},
{"id":"3","tagName":"banana"},
{"id":"4","tagName":"watermelon"},
{"id":"5","tagName":"pineapple"}
]
wh_index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script type="text/javascript" src="../js/jquery.js" ></script>
</head>
<body>
<script>
$(function(){
/*在Chrome中，它显示在控制台下面的错误：
Uncaught TypeError: Cannot use 'in' operator to search for '156'
in [{"id":"1","tagName":"apple"}...
解决方案：JSON字符串转换为JavaScript对象。
要修复它，通过标准JSON.parse()或jQuery 的 $.parseJSON 将其转换为JavaScript对象。
*/
var json = '[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},{"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},{"id":"5","tagName":"pineapple"}]';
setTimeout(function(){
$.each(JSON.parse(json), function(idx, obj) {
//console.log(obj.tagName);
});
},"1000");
//使用js处理json格式的txt文件
setTimeout(function(){
$.get("wh_data.txt",function(data){
$.each(JSON.parse(data), function(idx, obj) {
//console.log(idx+"---"+obj.tagName);
});
});
},"1000");
/* $.getJSON与$.get区别：
* $.getJSON已经明确是获取JSON格式的文件数据
* $.get是获取整个文件内容，若是JSON格式，还需要处理解析成JSON格式
*
* 若在$.getJSON中，再次将回调函数的数据解析的话，会报如下错误
*
* VM308:1 Uncaught SyntaxError: Unexpected token o in JSON at position 1 at JSON.parse (<anonymous>)
*/
setTimeout(function(){
$.getJSON("wh_data.txt",function(data){
$.each(data, function(idx, obj) {
//console.log(obj.tagName);
});
});
},"1000");
//问题，如何在轮询推送的同时，每次推送的是下一个JSON格式中的元素
var num=0;
setInterval(function(){
$.getJSON("wh_data.txt",function(data){
$.each(data, function(idx, obj) {
if(0==num){ //num: 1 idx 0---apple
console.log("num: "+num+" idx "+idx+"---"+obj.tagName);
}else if(idx==num){ //num: 1 idx 0---apple
console.log("num: "+(num%5)+" idx "+idx+"---"+obj.tagName);
}
});
});
num++;
},"1000");
});
</script>
</body>
</html>