jQuery.each( collection, callback(indexInArray, valueOfElement) )
Returns: Object
Description: A generic iterator function, which can be used to seamlessly iterate over both objects and arrays. Arrays and array-like objects with a length property (such as a function's arguments object) are iterated by numeric index, from 0 to length-1. Other objects are iterated via their named properties.
jQuery.each( collection, callback(indexInArray, valueOfElement) )
version added: 1.0
The object or array to iterate over.
callback(indexInArray, valueOfElement)
The function that will be executed on every object.
The $.each() function is not the same as .each(), which is used to iterate, exclusively, over a jQuery object. The $.each() function can be used to iterate over any collection, whether it is a map (JavaScript object) or an array. In the case of an array, the callback is passed an array index and a corresponding array value each time. (The value can also be accessed through the this keyword, but Javascript will always wrap the this value as an Object even if it is a simple string or number value.) The method returns its first argument, the object that was iterated.
$.each([52, 97], function(index, value) {
alert(index + ': ' + value);
});
This produces two messages:
0: 52
1: 97
If a map is used as the collection, the callback is passed a key-value pair each time:
var map = {
'flammable': 'inflammable',
'duh': 'no duh'
};
$.each(map, function(key, value) {
alert(key + ': ' + value);
});
Once again, this produces two messages:
flammable: inflammable
duh: no duh
We can break the $.each() loop at a particular iteration by making the callback function return false. Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.
Examples
Example 1
Iterates through the array displaying each number as both a word and numeral var arr = [ "one", "two", "three", "four", "five" ];
var obj = { one:1, two:2, three:3, four:4, five:5 };
jQuery.each(arr, function() {
$("#" + this).text("My id is " + this + ".");
return (this != "four"); // will stop running to skip "five"
});
jQuery.each(obj, function(i, val) {
$("#" + i).append(document.createTextNode(" - " + val));
});
Example 1- Full source:
<!DOCTYPE html> <html> <head> <script src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript" language="javascript"> $(document).ready(function(){ var arr = [ "one", "two", "three", "four", "five" ]; var obj = { one:1, two:2, three:3, four:4, five:5 }; jQuery.each(arr, function() { $("#" + this).text("My id is " + this + "."); return (this != "four"); // will stop running to skip "five" }); jQuery.each(obj, function(i, val) { $("#" + i).append(document.createTextNode(" - " + val)); }); }); </script> <style> div { color:blue; } div#five { color:red; } </style> </head> <body> <div id="one"></div> <div id="two"></div> <div id="three"></div> <div id="four"></div> <div id="five"></div> </body> </html>
Example 2
Iterates over items in an array, accessing both the current item and its index.$.each( [0,1,2], function(i, n){
alert( "Item #" + i + ": " + n );
});
Example 3
Iterates over the properties in an object, accessing both the current item and its key.$.each( { name: "John", lang: "JS" }, function(i, n){
alert( "Name: " + i + ", Value: " + n );
});
Was this information helpful?
