I have a form and it contains multiple input fields. What if i don't provide an id or name to each and every field. will that field be submitted with some default name or won't be submitted at all.
This is just a query. No code involved.
Thanks
Form controls without names cannot be successful controls and will not be submitted.
The value of a control without a name will not be included in the submitted form data.
See HTML 4:
A successful control is "valid" for submission. Every successful control has its control name paired with its current value as part of the submitted form data set. A successful control must be defined within a FORM element and must have a control name.
or HTML 5:
If any of the following conditions are met, then skip these substeps for this element … The field element is not an input element whose type attribute is in the Image Button state, and either the field element does not have a name attribute specified, or its name attribute's value is the empty string.
The id is irrelevant to the success of a control. Only the name matters there.
The id is still important to include as it is the best way to associate a <label> element with a control (and has other uses via JS and CSS).
The form will still get submitted but you won't be able to get the 'post' values when the form has been submitted.
Related
I have an edit page where several fields are conditionally disabled, based on the user's role. When the fields are disabled, their values are not posted to the server (as expected), which causes the ModelState to be invalid, as the values are required.
To get around this, I want to add Html.HiddenFor() for the fields; so that a value will still get posted (and so that it will retain those values if the View is returned). However, in the case that those fields are not disabled, I will then have both a TextBoxFor and a HiddenFor going to the same model property.
I have run a couple tests, and it appears that when this happens, the value of the first element on the form will be binded to the model, while the next one just gets ignored. If this is the case, then I should be able to just put the HiddenFor after the TextBoxFor, in which case the value of the hidden input will only be posted when the regular input is disabled.
#Html.TextBoxFor(m => m.FirstName)
#Html.HiddenFor(m => m.FirstName) #*Only gets binded to the model if the above text box is disabled*#
(There is some JavaScript that conditionally disabled the visible TextBox).
So two questions: 1) Is it documented that MVC binding will always work this way; can I safely have both of these fields?
And, 2) Is there a better approach to accomplishing this? I know that I can but the HiddenFor inside an #If statement so that it will only get created if the TextBox is disabled; but that is a lot of extra logic in the View that I'd like to avoid.
The DefaultModelBinder reads the values from the request in order and binds the first matching name/value pair and ignores subsequent matches (unless the property is IEnumerable). This is how the CheckBoxFor() method ensures a true or false value is always submitted to the controller (the method generates a checkbox with value="True" and a hidden input with value="False"), so you can safely add the hidden input after the textbox.
One option you might consider rather than a disabled textbox, is to make it readonly, which means it will always submit a value, therefore you only need one input (and you can always style it to look disabled if that is what you want).
if you have
<button class="button yellow" type="submit"
name="button">Log in</button>
and you submit it, what gets posted to the server for the button which has a name but no value attribute?
The reason I ask is that I'm parsing HTML forms, and need to post the named values that send data to the server. I got the others covered, but wasn't sure about button.
According to the HTML Spec, a button's value is either determined by its value attribute or is an empty string. A button's value is only submitted with the form if the button has a name and is used to initiate form submission. If the button in your example is clicked, the resultant submission will be:
"button=" (quotes added)
Some browsers (mainly older IE versions) have incorrect implementations of this button behaviour that either set the value to the button's contents or submit all button values regardless of initiation source.
button does not get posted to server when the form is posted. Only input type's like text, password, select elements etc., which accepts user inputs will be posted to the server
Button never supplies value to form. It just provides a submit event that tells the browser to submit that form with all the input tags to the action attribute inside your form tag using the method attribute value. Button only provides the event and not the values.
There will be nothing posted to the server for buttons. When you click a button, it invokes the action of submit, that is all.
I tried it out by printing the request.POST in django.
This image shows a "Log in" button with no value but name="button", as asked
The console shows
< QueryDict: {u'csrfmiddlewaretoken': [u'9aAx..'], u'sensor': [u'sd1'], u'button':[u'']}>
So, in this case, the form is sent as a dictionary and for the buttons the key, value pair is "button" : " ". So, if you try to get value of this button with request.POST.get, you will get NULL.
So, the answer to your question is the form consolidates all the input values, which can be accessed with their 'name' including buttons. If no value is provided, it returns NULL.
I'm having a problem with a template: I'm trying to display a form for changing a value, in which the user enters the current value in a textarea and the old value is kept inside a hidden field for auditing purposes. This value is generally some HTML, and when I render the page this HTML in the hidden field seems to get partially rendered: the value attribute of my hidden field gets closed by the first quotation marks inside the entered HTML, and the rest of the HTML spews out onto my page. I've tried using the escape decorator but that hasn't changed anything.
Firstly, a better solution might be to keep the audit value in a separate model field defined with editable=False. You can still perform checks against the value in a form's clean method:
def clean(self):
cleaned_data = super(SomeForm, self).clean()
if instance.the_audit_field == cleaned_data['the_editable_field']:
...raise a validation error?
You can also modify the value of the audit field from within the model's save method.
Secondly, assuming you must do it the way you are now, let me address the non-escaped value in your template. I assume you're using something like the following:
<textarea value="{{ form.the_audit_field.value }}"></textarea>
You should instead use the following:
<textarea>{{ form.the_audit_field.value }}</textarea>
Note, the value goes inside the textarea, instead of in the value attribute of it.
An even better way to do it is to simply allow Django to render the field for you like the following:
{{ form.the_audit_field }}
Alright, so I'm pretty new to Spring, but I was asked to resolve a bug. So in our application, we have a page that queries a database based on an id. However, not all entries are unique to the id. The id and date pair, on the other hand, do define unique entries.
So this page takes in an id. If there is only a single entry related to this id, everything works fine. However, if there are multiple entries, the page displays a radio button selection of the various dates that pertain to that id. We use something like:
< form:radiobutton id="loadDate" path="loadDate" value="${date}" label="${date}" />
Later on the same page, we want to display the data for that option. As part of it, we display the date of that selection:
< form:input id="aiLoadDate" path="loadDate" maxlength="22" size="22" class="readonly" readonly="true"/>
The problem is that when this happens, the variable (or bean? I'm not quite sure about Spring yet..) loadDate (a string) ends up being the same date twice, seperated with a comma. I'm guessing the problem here is the "path="loadDate"" that is common to both lines.
Instead of appending the date to the already existing one like a csv, I'd like it to overwrite the current entry intead. Is there a way to do this?
Spring is not the direct cause of your problem. When the elements of an HTML form are submitted, each element will appear in the request as a name=value pair. If two or more elements in the form have the same name (not id, name attribute) then those elements appear in the request as name=value,value (with one value per element with a duplicated name).
Option 1: stop using an input as a display element. Just display the date in a span (or div or paragraph or what ever). If you want the look of an input box (border, etc.) use CSS to create a class that has the look you want and attach the class to the span (or div or paragraph, etc) in which you display the date.
Option2: continue using an input as a display element. Disabled input elements are not added to the request when the form is submitted. in the form:imput set disabled="true".
I have access to form field in the administrative view.
Example
<label>Number:</label>
<input type="text" name="title" size="50"/><br/>
I do not have access to modify the html syntax, the only thing i can do is updating the form field with a value.
In the form field i want to update it with a number. I also want to have a link assigned to that number.
So when i click that number it directs us to the link.
Is there a way i can do that?
This method is tedious, but you could use the jQuery nth-selector to select the specific form element that you are dealing with.
http://api.jquery.com/nth-child-selector/
This method is risky, however, since you might add other form elements before it, altering the index of your target input element.
Afterwords, you could use the .val() jQuery method to change your input value.
Nonetheless, again, this method is not safe because the index of the form element could change. I would beg the powers of be to be able to add an ID or some identifying attribute to that form element.