How can I get javascript to read from a .json file?
My script currently looks like this:
<script type="text/javascript">
function updateMe(){
var x = 0;
var jsonstr = '{"date":"July 4th", "event":"Independence Day"}';
var activity=JSON.parse(jsonstr);
开发者_运维知识库 while(x<10){
date = document.getElementById("date"+x).innerHTML = activity.date;
event = document.getElementById("event"+x).innerHTML = activity.event;
x++;
}
}
</script>
Where date"x" and event"x" are a series of html tags. This function runs when the page loads (onload). My goal is to do this exact same thing, only from a local .json file as opposed to the hard code that I've got above. I've already checked out http://api.jquery.com/jQuery.getJSON/.
The local .json file looks like this:
{"date":"July 4th", "event":"Independence Day"}
Any suggestions?
Assuming you mean "file on a local filesystem" when you say .json file.
You'll need to save the json data formatted as jsonp, and use a file:// url to access it.
Your HTML will look like this:
<script src="file://c:\\data\\activity.jsonp"></script>
<script type="text/javascript">
function updateMe(){
var x = 0;
var activity=jsonstr;
foreach (i in activity) {
date = document.getElementById(i.date).innerHTML = activity.date;
event = document.getElementById(i.event).innerHTML = activity.event;
}
}
</script>
And the file c:\data\activity.jsonp contains the following line:
jsonstr = [ {"date":"July 4th", "event":"Independence Day"} ];
NOTICE: AS OF JULY 12TH, 2018, THE OTHER ANSWERS ARE ALL OUTDATED. JSONP IS NOW CONSIDERED A TERRIBLE IDEA
If you have your JSON as a string, JSON.parse() will work fine. Since you are loading the json from a file, you will need to do a XMLHttpRequest to it. For example (This is w3schools.com example):
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var myObj = JSON.parse(this.responseText);
document.getElementById("demo").innerHTML = myObj.name;
}
};
xmlhttp.open("GET", "json_demo.txt", true);
xmlhttp.send();<!DOCTYPE html>
<html>
<body>
<h2>Use the XMLHttpRequest to get the content of a file.</h2>
<p>The content is written in JSON format, and can easily be converted into a JavaScript object.</p>
<p id="demo"></p>
<p>Take a look at <a href="json_demo.txt" target="_blank">json_demo.txt</a></p>
</body>
</html>It will not work here as that file isn't located here. Go to this w3schools example though: https://www.w3schools.com/js/tryit.asp?filename=tryjson_ajax
Here is the documentation for JSON.parse(): https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
Here's a summary:
The JSON.parse() method parses a JSON string, constructing the JavaScript value or object described by the string. An optional reviver function can be provided to perform a transformation on the resulting object before it is returned.
Here's the example used:
var json = '{"result":true, "count":42}';
obj = JSON.parse(json);
console.log(obj.count);
// expected output: 42
console.log(obj.result);
// expected output: trueHere is a summary on XMLHttpRequests from https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest:
Use XMLHttpRequest (XHR) objects to interact with servers. You can retrieve data from a URL without having to do a full page refresh. This enables a Web page to update just part of a page without disrupting what the user is doing. XMLHttpRequest is used heavily in Ajax programming.
If you don't want to use XMLHttpRequests, then a JQUERY way (which I'm not sure why it isn't working for you) is http://api.jquery.com/jQuery.getJSON/
Since it isn't working, I'd try using XMLHttpRequests
You could also try AJAX requests:
$.ajax({
'async': false,
'global': false,
'url': "/jsonfile.json",
'dataType': "json",
'success': function (data) {
// do stuff with data
}
});
Documentation: http://api.jquery.com/jquery.ajax/
You can do it like... Just give the proper path of your json file...
<!doctype html>
<html>
<head>
<script type="text/javascript" src="abc.json"></script>
<script type="text/javascript" >
function load() {
var mydata = JSON.parse(data);
alert(mydata.length);
var div = document.getElementById('data');
for(var i = 0;i < mydata.length; i++)
{
div.innerHTML = div.innerHTML + "<p class='inner' id="+i+">"+ mydata[i].name +"</p>" + "<br>";
}
}
</script>
</head>
<body onload="load()">
<div id= "data">
</div>
</body>
</html>
Simply getting the data and appending it to a div... Initially printing the length in alert.
Here is my Json file: abc.json
data = '[{"name" : "Riyaz"},{"name" : "Javed"},{"name" : "Arun"},{"name" : "Sunil"},{"name" : "Rahul"},{"name" : "Anita"}]';
Actually, you are looking for the AJAX CALL, in which you will replace the URL parameter value with the link of the JSON file to get the JSON values.
$.ajax({
url: "File.json", //the path of the file is replaced by File.json
dataType: "json",
success: function (response) {
console.log(response); //it will return the json array
}
});
Instead of storing the data as pure JSON store it instead as a JavaScript Object Literal; E.g.
window.portalData = [
{
"kpi" : "NDAR",
"data": [15,152,2,45,0,2,0,16,88,0,174,0,30,63,0,0,0,0,448,4,0,139,1,7,12,0,211,37,182,154]
},
{
"kpi" : "NTI",
"data" : [195,299,31,32,438,12,0,6,136,31,71,5,40,40,96,46,4,49,106,127,43,366,23,36,7,34,196,105,30,77]
},
{
"kpi" : "BS",
"data" : [745,2129,1775,1089,517,720,2269,334,1436,517,3219,1167,2286,266,1813,509,1409,988,1511,972,730,2039,1067,1102,1270,1629,845,1292,1107,1800]
},
{
"kpi" : "SISS",
"data" : [75,547,260,430,397,91,0,0,217,105,563,136,352,286,244,166,287,319,877,230,100,437,108,326,145,749,0,92,191,469]
},
{
"kpi" : "MID",
"data" : [6,17,14,8,13,7,4,6,8,5,72,15,6,3,1,13,17,32,9,3,25,21,7,49,23,10,13,18,36,9,12]
}
];You can then do the following in your HTML
<script src="server_data.js"> </script>
function getServerData(kpiCode)
{
var elem = $(window.portalData).filter(function(idx){
return window.portalData[idx].kpi == kpiCode;
});
return elem[0].data;
};
var defData = getServerData('NDAR');
加载中,请稍侯......
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