## partial derivative – find the canonical form of the hyperbolic PDE \$ a (x, y) u_ {xx} + 2b (x, y) u_ {xy} + c (x, y) u_ {yy} + F (x, y , u, u_x, u_y) = \$ 0

So the question is trying to transform in the hyperbolic case, the PDE

$$a (x, y) u_ {xx} + 2b (x, y) u_ {xy} + c (x, y) u_ {yy} + F (x, y, u, u_x, u_y) = 0$$

can be transformed into normal form

$$widetilde {u} _ {ξ eta} + { Psi} (ξ, eta, widetilde {u}, widetilde {u} _ξ, widetilde {u} _η)$$

I know the steps to follow for this. However, I don't know how to apply some of them. For example, what does F represent in this case. Where would it be in the second-order general EDP? For example, here A = a, B = 2b and C = 1. Am I on the right track? I just need to know what each constant is and how to handle F and I can move on from there.

Thanks for the help.

## Entity type manager: how to retrieve web form entries with conditions Webform_submission_data

Don't think you can query web form fields like entity fields, but it should be possible in an SQL selection query:

``````\$submission_storage = Drupal::entityTypeManager()->getStorage('webform_submission');

\$query = Drupal::database()->select('webform_submission_data')
->fields('webform_submission_data', ('sid'))
->condition('webform_id', 'my_form_id')
->condition('name', 'field_account_type')
->condition('value', 'normal')
->distinct();

\$ids = \$query->execute()->fetchCol();

``````

If you also want to query the uid from the main table, join the two tables:

``````\$submission_storage = Drupal::entityTypeManager()->getStorage('webform_submission');

\$query = Drupal::database()->select('webform_submission_data', 'd');
\$query->join('webform_submission', 's', 'd.sid = s.sid');
\$query->fields('d', ('sid'))
->condition('d.webform_id', 'my_form_id')
->condition('s.uid', \$uid)
->condition('d.name', 'field_account_type')
->condition('d.value', 'normal')
->distinct();

\$ids = \$query->execute()->fetchCol();

``````

## frame ticks in scientific form on a double axis y

I need plots with tick marks on the y axis (right and left) in scientific form as well as equally spaced (unlike ListLogPlot) to plot the data present as data with 3 columns.

## magento2 – Result of the action of the administration menu of Magento 2 Invalid security key or form. Please refresh the page. on click

Forgive me for my question. Still new with magento 2.

So I managed to add a new admin menu. But the problem is that every time I click on the admin menu button, I receive an invalid security or form key. Please refresh the page.

Here are some of my codes.

This is my menu.xml

``````
``````

And here are my directories.

## Disable summary of validation errors on the Drupal 8 form

I am using Drupal 8. When using the "webform" module with the "inline form error" module, it displays both the summary of validation errors above and each field error under the field. How to disable the above error messages?
Here is the screenshot.

## How can I improve this request form?

We have reduced the number of questions asked to users. Once the request form is clicked, we have a secondary layer for the form which is an overlay.
Is there a way to improve this better?

## How to submit the form by pressing Ctrl + S (instead of "save web page") in JavaScript?

I have an HTML page with a form. I don't want to have to move the cursor to and constantly click on the "Update" button. I want to be able to just press "Ctrl + S" as if it were a text editor, to submit the form (which saves the fields).

No jQuery junk, please.

## 8 – Create a node from a web form submission

You tried to create a node from a web form submission to no avail, using the second answer here: How to create a node from a web form submission?

The first answer I could make, the second – the one I really want – I couldn't. The steps:

1. Module created (with Drupal console).
2. Creating a web form
3. Manager added (email)
4. Addition of MyWebformHandler.php (according to StackOverflow response)

It did not work.

## 8 – How to use Twig tempalte to manage the label of the form input field?

In a custom module (association), I have a form (MembershipStep3).
I would like to use the Twig template to manage the titles of form fields and I need advice on this.
In `association.module`, I have this code:

``````function association_theme()
{
return (
'association' => (
'render element' => 'children',
),
'membership_step3' => (
'render element' => 'form',
'template' => 'membership-step3',
),
);
}
``````

In `MembershipStep3.php`, two almost identical fields are defined this way:

``````  public function buildForm(array \$form, FormStateInterface \$form_state) {

\$form = parent::buildForm(\$form, \$form_state);
\$form('amap1') = (
'#type' => 'checkbox',
'#title' => 'Je souhaite faire partie de l’AMAP (cas 1)',
);
\$form('amap2') = (
'#type' => 'checkbox',
);
some other stuff...
``````

And here `membership-step3.html.twig`:

`````` {{ form.form_build_id }} {{ form.form_token }} {{ form.form_id }}

{{ form.amap1 }}

{{ form.amap2 }}

Je souhaite faire partie de l’AMAP (cas 2)

{# Renders the rest of the form #} {{ form | without('amap1', 'amap2') }}

``````

The result is:

The generated HTML code is:

``````

Je souhaite faire partie de l’AMAP (cas 1)

Je souhaite faire partie de l’AMAP (cas 2)

``````

As you can see, the label of `amap2`is outside the div created by `{{ form.amap2 }}`.

How can I change my Twig model in order to get a result similar to `amap1`?

## user behavior – Preloader for the search form

I have a tool (webapp) that allows people to search my database. They can choose filters and sort their results, etc. I wanted to add to the experience to let the user know that their search is loading, once they click the submit button.

So the search form looks like this

*** SEARCH FIELD || SUBMIT BUTTON ****

* FILTERS *

* RESULTS *

I am trying to decide between:

• the send button transforming into a graphic preloader. It therefore initially has a value of “SEARCH”, at the click, it is replaced by a gif of preloading, to give the effect of a loading. It's cool, tidy and simple.
• or a preloader in the center of the screen. This should also be accompanied by a layer of transparency on the top of the current screen, to make the preloader more noticeable. It sounds a bit of an exaggeration, and it's the same as everyone else.
• another thought, would be to delete all the current search results and replace them with a preloader (the results will come when reloading the NON ajax page).

I think none of them will have much effect on conversions. I was more concerned with the actual experience. I want people to know that when they clicked the search button, we have received their request and are loading their results, especially if the search takes time.

I am open to other ideas.