Why does this code always return 0?
var possibleMatches = new Array();
$.getJSON('getInformation.php', function(data) {
$.each(data, function(i){
possibleMatches.push(data[i]);
})
});
alert(possibleMatches.length);
Though I can move or add "alert(possibleMatches.length);" inside the $.each and it will output the correct number of elements.
I'm just curious as to why it the values aren't going into the array as I expected. I'm sure its a local variable vs. global variable issue, just not sure why.
Basically, what this is trying to do is fill the possibleMatches array with the data results.
thanks!
Why does this code always return 0?
var possibleMatches = new Array();
$.getJSON('getInformation.php', function(data) {
$.each(data, function(i){
possibleMatches.push(data[i]);
})
});
alert(possibleMatches.length);
Though I can move or add "alert(possibleMatches.length);" inside the $.each and it will output the correct number of elements.
I'm just curious as to why it the values aren't going into the array as I expected. I'm sure its a local variable vs. global variable issue, just not sure why.
Basically, what this is trying to do is fill the possibleMatches array with the data results.
thanks!
Share Improve this question asked Mar 9, 2010 at 16:58 psiko.scweekpsiko.scweek 851 silver badge5 bronze badges3 Answers
Reset to default 6Asynchronicity. The line alert(possibleMatches.length);
executes before the success callback for $.getJSON()
executes.
So, to have your alert report accurately, just move it.
var possibleMatches = new Array();
$.getJSON('getInformation.php', function(data) {
$.each(data, function(i){
possibleMatches.push(data[i]);
})
// To here
alert(possibleMatches.length);
});
// From here
Remember, the first A in AJAX stands for "Asynchronous"
$.getJSON
performs an asynchronous call, whose callback is executed on pletion of the xmlhttprequest used:
var possibleMatches = new Array();
$.getJSON('getInformation.php', function(data) { // <-- this will run later
$.each(data, function(i){
possibleMatches.push(data[i]);
})
});
alert(possibleMatches.length); // this will call immediately
The jetJSON request is asynchronous, it finished after your alert runs. If you want an accruate alert, it should be in your callback for getJSON
like this:
$.getJSON('getInformation.php', function(data) {
$.each(data, function(i){
possibleMatches.push(data[i]);
});
alert(possibleMatches.length);
});