all | NN n/a IE 4 DOM n/a
A collection of elements nested within the current element. A reference to document.all, for example, returns a collection (array) of all element objects contained by the document, including elements that may be deeply nested inside the document's first level of elements. The collection is sorted in source code order of the element tags.
Object Model Reference
IE | elementReference.all

length | NN n/a IE 4 DOM n/a
| Read-only
Returns the number of elements in the collection.
Example
    var howMany = document.all.length
Value Integer.

item( ) | NN n/a IE 4 DOM n/a
item(index[, subindex]) Returns a single object or collection of objects corresponding to the element matching the index value (or, optionally, the index and subindex values).
Returned Value One object or collection (array) of objects. If there are no matches to the parameters, the returned value is null.
Parameters
index | When the parameter is a zero-based integer, the returned value is a single element corresponding to the specified item in source code order (nested within the current element); when the parameter is a string, the returned value is a collection of elements whose id or name properties match that string.
subindex | If you specify a string value for the first parameter, you can use the second parameter to specify a zero-based index that retrieves the specified element from the collection whose id or name properties match the first parameter's string value.

tags( ) | NN n/a IE 4 DOM n/a
tags(tagName) Returns a collection of objects (among all objects nested within the current element) whose tags match the tagName parameter.
Returned Value A collection (array) of objects. If there are no matches to the parameters, the returned value is an array of zero length.
Parameters
tagName | A string that contains the all-uppercase version of the element tag, as in document.all.tags("P").