Question

In the following code excerpt, products is a xml nodelist, which structure is:

<products>
  <product>
    <id>1</id>
    <name>item1</name>
  </product>
  <product>
    <id>2</id>
    <name>item2</name>
  </product>
</products>



xml = httpRequest.responseXML
products = xml.getElementsByTagName('products')


products[0].constructor
//=>ElementConstructor

product = products[0]
//=><product>…</product>

product.constructor
//=>ElementConstructor

product.getElementsByTagName('id')
//[ <id>1</id> ]

for(product in products){product.getElementsByTagName('id')}
//=>TypeError: 'undefined' is not a function (evaluating 'product.getElementsByTagName('id')')

how can I iterate each <product> element in <products> element, and select only tag

Answer 1

for(product in products):

• iterates over all the enumerable properties of the object, not just the ones with numbers for the property name
• gives you the property names, not the values

This code:

var products = document.getElementsByTagName('body');
for(product in products) { console.log(product); }

Gives:

0
length
item

If you want to loop over the elements, then you need to use a regular for loop.

for (var i = 0; i < products.length; i++) {
    var product = products[i];
    // do something with product
}