问题
I've been using
document.forms[0].fieldname.value
to get values in javascript from a form, but I'd like to use a name to reference the field and not a 0, what would be the equivalent these days since <form name="formname"> isn't compliant?
回答1:
The easiest way is to add an id to the input: <input id="fieldname" /> and reference the value from JavaScript like so:
document.getElementById('fieldname').value
or, if you're using jQuery
$('#fieldname').val();
回答2:
The forms collection is standard DOM 1, there is nothing wrong with using it.
document.forms.formId.elements.field
回答3:
Would giving the form a name= value and referring to it in the document.forms 'array' by name work?
i.e.: (much abbreviated)
<form name="form1">.insert.your.elements.here.with.name.attribute.set.</form>
and in JS:
document.forms["form1"]["form_item_name"].value;
I'm a rank amateur so if this is wrong, pls leave me a constructive criticism... :-)
回答4:
Giving each element an unique id and using this id with the getElementById function is recommended:
var value = document.getElementById('idofelement').value;
回答5:
(document.forms is still supported. You can keep it.)
The best way to to give the field an id and use document.getElementById.
<input type="text" name="fooName" id="fooId" />
...
document.getElementById("fooId").value;
If you can't add an id, you can still use document.getElementsByName, but it will return an array instead of a single element because many may share the same name.
document.getElementsByName("fooName")[0].value;
来源：https://stackoverflow.com/questions/2810573/w3c-document-forms0-fieldname-equivalent