Getting reference to form with no id or name - javascript

I am working on a project where I need to recall the fields entered in a form so I can repopulate them later. When a form has a name, I can remember it and then later use some JavaScript (document.getElementsByName(...)[0]) to access it. However, if there is no name...I'm at a loss for how to get a reference to it later.
I'm using jQuery, but am open to a JavaScript solution as well. One idea is to remember the index of the form. So, if it was document.forms[3] then later I can use the index. However, when someone submits a form, how do I know the index of the form that it is? (NOTE: I am blindly adding submit handlers to all forms when a page loads to capture the activity.)

Instead of attaching events to the submit buttons, attach it to the <form> elements directly, like this:
$("form").submit(function() {
//do something with this
//this == the form element being submitted
});
Or...in your current event handlers, use .closest() to get the closest parent <form> element:
$(":submit").click(function() {
var form = $(this).closest("form");
});

If you don't want to use an index on all form (flaky because someone may add a form in anywhere), you could use its surroundings as a reference... for example.
$('#content').parent().next().find('form')

Related

How to initialize form additions for jquery methods?

I've got a form where I'm trying to do the sort of thing you often see with tags: there's a textfield for the first tag, and, if you put something into it, a new and similar textfield appears to receive another tag. And so on. I've gotten the basics of this working by setting up a jQuery .blur() handler for the textfield: after the value is entered and the user leaves the field, the handler runs and inserts the new field into the form. The handler is pretty vanilla, something like:
$('input.the_field_class').blur(function () { ... });
where .the_field_class identifies the input field(s) that collect the values.
My problem is that, while the new textfield is happily added to the form after the user enters the first value, the blur handler doesn't fire when the user enters something into the newly-added field and then leaves it. The first field continues to work properly, but the second one never works. FWIW, I've watched for and avoided any id and name clashes between the initial and added fields. I had thought that jQuery would pick up the added textfield, which has the same class markings as the first one, and handle it like the original one, but maybe I'm wrong -- do I need to poke the page or some part of it with some sort of jQuery initialization thing? Thanks!
Without seeing your code in more of its context, it's hard to know for sure, but my best guess is that you're attaching a handler to the first field, but there is no code that gets called to attach it to the new field. If that's the case, you have a few options, two of which are:
1) In your blur() handler, include code to attach the blur handler to the newly created field.
2) Use jQuery's event delegation to attach a handler to the field container, and listen for blur events on any field in the container:
<div class="tag-container">
<input class="the_field_class" /> <!-- initial tag field -->
</div>
<script>
var $tagContainer = $('.tag-container');
var createNewField = function() {
$tagContainer.append($('<input class="the_field_class" />');
};
$tagContainer.on('blur', 'input.the_field_class', createNewField());
</script>
Which is better will depend on your use case, but I'd guess that the 2nd option will be better for you, since you're unlikely to be dealing with tons of blur events coming from the container.

Process each form fields in a form using JQuery

I have many questions based on form. I don't know the title suits or not. I created a JSP page and contains a form. It has many fields like input, select, textarea.
First is I want to count the number of fields in the form using JQuery. I tried the following.
var ln=$("#fileUpload").find('input,select,textarea').length;
alert(ln);
The form has one select box, 3 input fields and a textarea. But it was giving 0, instead of 5.(#fileUpload is the form id I want to submit)
How to get the exact number of fields?
Next is, I want to get each element in the form and find some attribute value. For examaple I want to get the name or id attribute for each element.
I would recommend using each() function:
$("#fileUpload input,select,textarea").each(function(){
console.log(this);
}
Btw: don't use alert, use console.log() instead ;)
You need to make sure that the form is loaded before your js script is launched.
To do so, wrap it in document ready like so:
$(function () {
var ln = $('#fileUpload').find('input, select, textarea').length;
alert(ln);
});
There should no problem in your code
Check that you have added the jquery and add an attribute to your form
id="fileUpload" then check
Also, check you don't have any other element having id fileUpload
like input type="file"
In your page <form id='fileUpload' ... > must be unique
Fiddle http://jsfiddle.net/qUJZf/

How to Call a javascript function when an event occurs in a page ?

I have a span with some value:
<li>Rent Collected: Euros <span id="rentTotal">2000</span></li>
I need the value to be update whenever user does any action in the page. Is there a way to do it without using onclick on all the elements?
Assuming this is using form elements to enter info, the form.onchange event is pretty handy for recalculations like that.
If you are not using form elements but instead using just HTML and lots of onclick code ... then this is why you should be using form elements instead.

Autosubmit form with existing 'submit' element

I have an HTML page with 1 form on it. So to auto-submit the form I could use this:
<body onload="document.forms[0].submit()">
However, there can be an element in the form with name="submit". This breaks the above code. Apart from removing or renaming the 'submit' field, is there another way to auto-submit a form?
Cheers.
Give the form an id and then use document.getElementById('id-of-your-form').submit();
Is there any particular reason that you'd want to keep a form element with name "submit"? Renaming that seems like it is the most pragmatic solution. Avoid name collisions when possible, and all that.
Assuming there is, give the form an ID and reference that.

How to reference a field within the current form only? -- JQuery beginner

I've tried all variations of the following:
$(this).("input[name='email']").val();
Assuming this is the form element, and you want to find input elements only with that form, you have a couple of options. You could use this as a context:
$("input[name='email']", this).val();
Or you could find the elements within this:
$(this).find("input[name='email']").val();
It depends on the context of this code, James has provided an answer for targeting inputs if you already have the desired form as your "context". But since there aren't a lot of ways to end up in that situation, and since you're looking for values I'm guessing that you're firing this code from a button inside the form, maybe a submit button?
In that case you'll have to traverse up the DOM before you can target your inputs and stay within the same form. Something like:
$(this).closest('form').find('input[name="email"]').val();

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