Question

Can any one explain what is the difference between

document.all

and the
document.forms[0] please?

Thank you

Answer 1

document.all gives you a reference to an array-like object containing all elements of the document in Internet Explorer (IE). Document.forms[0] gives you a pointer to the first form element in the document, in all browsers

The 2 are quite different then. If your form had a name attribute, say ‘myform’, then in IE that form could be referenced with document.all.myform

document.all is deprecated from IE version 5 and up. You can still use it though, even in IE9 it’s still available. Often it’s used to test if the browser is IE:

if (document.all) {
  //o no, it's IE again! We have to do it another way!
}

Referencing forms in the form of document.forms[0] is considered bad practice. More on that can be found here

NOTE: Since this answer was first written IE11 has been introduced which dropped support for document.all See Compatibility changes in IE11 for more information