How can I dynamically construct a document element string using a variable in Javascript?

This is driving me nuts, and I'm sure it's both possible and surely simple to do.

I have a page with a whole bunch of dynamically created forms on it. In one of my functions, I need to access one of those forms, so I pass the name of the form in a variable.

Then I need to access the name of that form using the document tree.

However, when I put in the variable, it assumes the name of the variable is the name of the form.

So this does not work:

function myAwesomeFunction(nameOfForm)
{
 var selection = document.nameOfForm.nameOfInput.selectedIndex;
}

So I looked around the net and saw that I need to use bracket notation, but this doesn't work either:

function myAwesomeFunction(nameOfForm)
{
 var selection = document[nameOfForm].nam开发者_如何转开发eOfInput.selectedIndex;
}

I also tried with some quotation action:

function myAwesomeFunction(nameOfForm)
{
 var selection = document['nameOfForm'].nameOfInput.selectedIndex;
}

... but no joy.

So, where am I going wrong?

For bonus points... what if both the name of the form and the name of the particular input were both dynamic? Then what?

function myAwesomeFunction(nameOfForm, nameOfInput)
{
 var selection = document[nameOfForm][nameOfInput].selectedIndex;
}

Look them up in the forms object - this won't work since it is an array and not an object.

use document.getElementsByName

function myAwesomeFunction(nameOfForm, nameOfInput)
{
 var selection = document.getElementsByName(nameOfForm)[nameOfInput].selectedIndex;
}

or even better, set an id attribuite on the form and use document.getElementById to find the form

Try using document.getElementById(nameOfForm) (if you have the ID on the form as well)...

If you can include a jQuery reference to your page, you can easily do the following (again assuming you have the ID on the form):

function myAwesomeFunction(nameOfForm, nameOfInput)
{
  var form = $("form#" + nameOfForm);
  var input = $("#" + nameOfInput + ":input");
  var selection = $(input).val();
}

function focusElement(formName, elemName) {
var elem = document.forms[formName].elements[elemName];
}
try this
formname is name of the form and elemname is input label name