CODEWITHSUNDEEP
javascript
slowD
slowD

Reputation: 339

javascript filter method doesn't work with getElementsByName

Why the following code doesn't work (alert is not executed)? custom_table is some file upload fields in html, its length is 10.

var custom_table=document.getElementsByName('custom_table');
var result = custom_table.filter( function (x)  { return x.value });
alert(result.length);

If I replace custom_table with names in the following code, it works fine.

var names = new Array();
var object = { name : "Joe", value:20, email: "[email protected]"};

names.push(object);
object = { name : "Mike", value:50, email: "[email protected]"};
names.push(object);
object = { name : "Joe", value:45, email: "[email protected]"};
names.push(object);

Thanks.

Upvotes: 2

Views: 2210

Answers (2)

Matt Greer
Matt Greer

Reputation: 62027

getElementsByName returns an HTMLCollection*, which is not an array. filter() is only on arrays. You can dump it into an array easily enough:

var elementCollection = document.getElementsByName('myname');
var elementArray = Array.prototype.slice.call(elementCollection, 0);
elementArray.filter(...); // this will now work

*or a NodeList, depending on the browser, the distinction isn't very important though

Upvotes: 3

Pointy
Pointy

Reputation: 413720

The return value from getElementsByName is not a JavaScript array. You can copy the contents into one, however:

var custom_table=document.getElementsByName('custom_table');
custom_table = [].slice.call(custom_table, 0);

Then .filter, .map, etc. will work.

Upvotes: 3

Related Questions