Due to security issues (same origin policy), javascript access to local files is restricted if without user interaction.
According to https://developer.mozilla.org/en-US/docs/Same-origin_policy_for_file:_URIs:
A file can read another file only if the parent directory of the
originating file is an ancestor directory of the target file.
Imagine a situation when javascript from a website tries to steal your files anywhere in your system without you being aware of. You have to deploy it to a web server. Or try to load it with a script tag. Like this:
<script type="text/javascript" language="javascript" src="jquery-1.8.2.min.js"></script>
<script type="text/javascript" language="javascript" src="priorities.json"></script>
<script type="text/javascript">
$(document).ready(function(e) {
alert(jsonObject.start.count);
});
</script>
Your priorities.json file:
var jsonObject = {
"start": {
"count": "5",
"title": "start",
"priorities": [
{
"txt": "Work"
},
{
"txt": "Time Sense"
},
{
"txt": "Dicipline"
},
{
"txt": "Confidence"
},
{
"txt": "CrossFunctional"
}
]
}
}
Or declare a callback function on your page and wrap it like jsonp technique:
<script type="text/javascript" language="javascript" src="jquery-1.8.2.min.js"> </script>
<script type="text/javascript">
$(document).ready(function(e) {
});
function jsonCallback(jsonObject){
alert(jsonObject.start.count);
}
</script>
<script type="text/javascript" language="javascript" src="priorities.json"></script>
Your priorities.json file:
jsonCallback({
"start": {
"count": "5",
"title": "start",
"priorities": [
{
"txt": "Work"
},
{
"txt": "Time Sense"
},
{
"txt": "Dicipline"
},
{
"txt": "Confidence"
},
{
"txt": "CrossFunctional"
}
]
}
})
Using script tag is a similar technique to JSONP, but with this approach it's not so flexible. I recommend deploying it on a web server.
With user interaction, javascript is allowed access to files. That's the case of File API. Using file api, javascript can access files selected by the user from <input type="file"/> or dropped from the desktop to the browser.
