window). Objects can be referred to by name or id or by their position on the page. For example, if there is a form on the page named "loginform", using dot notation you could refer to the form as follows:
loginform is the first form on the page, you could also refer to this way:
document can have multiple
form elements as children. The number in the square brackets (
) indicates the specific
form in question. In programming speak, every
form on the page is referenced with the number zero (
0) as shown in the syntax example above.
Objects can also be referenced using square bracket notation as shown below:
window['document']['loginform'] // and window['document']['forms']
Dot notation and square bracket notation are completely interchangeable. Dot notation is much more common; however, as we will see later in the course, there are times when it is more convenient to use square bracket notation.
window object is always the implicit top-level object and therefore does not have to be included in references to objects. For example,
window.document.forms can be shortened to