Cronjob but for jQuery/Javascript - php

Question

I'm trying to develop a web application that mainly uses PHP but i'm using jQuery/Javascript to grab people's Tweets from their URL: http://twitter.com/status/user_timeline/joebloggs.json?count=1&callback=?
The thing is want to run a PHP cron job to grab latest tweets from people who have signed up for my application. But i dont know how to do this with javascript?
Is this possible?
EDIT:
This is the javascript code, can i do this in PHP so i can use a Cron Job?
$(document).ready( function() {
var url = "http://twitter.com/status/user_timeline/joebloggs.json?count=1&callback=?";
$.getJSON(url,
function(data){
$.each(data, function(i, item) {
$("#twitter-posts").append("<p>" + item.text.linkify() + " <span class='created_at'>" + relative_time(item.created_at) + " via " + item.source + "</span></p>");
});
});
});
String.prototype.linkify = function() {
return this.replace(/[A-Za-z]+:\/\/[A-Za-z0-9-_]+\.[A-Za-z0-9-_:%&\?\/.=]+/, function(m) {
return m.link(m);
});
};
function relative_time(time_value) {
var values = time_value.split(" ");
time_value = values[1] + " " + values[2] + ", " + values[5] + " " + values[3];
var parsed_date = Date.parse(time_value);
var relative_to = (arguments.length > 1) ? arguments[1] : new Date();
var delta = parseInt((relative_to.getTime() - parsed_date) / 1000);
delta = delta + (relative_to.getTimezoneOffset() * 60);
var r = '';
if (delta < 60) {
r = 'a minute ago';
} else if(delta < 120) {
r = 'couple of minutes ago';
} else if(delta < (45*60)) {
r = (parseInt(delta / 60)).toString() + ' minutes ago';
} else if(delta < (90*60)) {
r = 'an hour ago';
} else if(delta < (24*60*60)) {
r = '' + (parseInt(delta / 3600)).toString() + ' hours ago';
} else if(delta < (48*60*60)) {
r = '1 day ago';
} else {
r = (parseInt(delta / 86400)).toString() + ' days ago';
}
return r;
}
function twitter_callback ()
{
return true;
}

Answer 1

The javascript method setInterval allows you to pass a method and a number of milliseconds. The method you provide will be executed every number of milliseconds you provided. So if you wanted to grab the latest tweets every 30 seconds, you would call something like this:
setInterval(updateTweets,30000);
This would call the method updateTweets every thirty seconds, where you could use ajax to load up the latest tweets.
For more information on setInterval, you can check out: http://www.elated.com/articles/javascript-timers-with-settimeout-and-setinterval/

Answer 2

The best solution is to re-implement your functionality in PHP:
<?
$url = "http://twitter.com/status/user_timeline/joebloggs.json?count=1&callback=?";
$responseJsonString = file_get_contents($url);
$responseArray = json_decode($responseJsonString, $array=true);
// uncomment this to see what's in the response array:
// print_r($responseArray);
// Now, you can do as you like with $responseArray
And then execute the PHP script via crontab.