Browser-based packet radio form entry & display
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


Inspired by Phil Henderson's elegant PacForms browser-based solution for creating and displaying message with a compact representation for packet radio transmission of the entered data, pack-it-forms is a respectful re-implementation with a number of advantages:

  1. All processing is done in-browser in Javascript: No external program is required for parsing the message data.

  2. Message encoding is derived from form markup: The field names used in the message text are derived from the name attribute of the input elements of the HTML form. There is no code specific to any field in a form.

  3. Forms are written in a declarative style: validation constraints and default contents are specified in the HTML description of the form rather than Javascript. A template substitution system enables dynamic generation of default values.

  4. Reuseable form behavior: The implementation of form behavior has been cleanly separated and made more generic so new forms can be easily created. A file inclusion mechanism allows reuse of sub-parts of forms as well.

  5. The full implementation is available to all for study and enhancement.

Using Forms


Originally there was only a single method of using pack-it-forms involving the Outpost radio messenger application and PacFORMs, but there are now several methods, each of which is implemented their own repository.

The Outpost+PacFORMS method is still the currently the recommended method, though it is hoped it will be obsolete in the near future. Installation instructions can be found in the

pack-it-forms outpost-pacread

project. As other methods are released they will be documented here.

Entering Data in a New Form

To enter data in a new form, open the HTML file for the form in your web browser. You can do this through appropriate menu entries in OutPost if you setup Outpost. Otherwise you can use your normal operating system file browser or command line to open the file. It may take a moment to load and will display a spinner to show activity is occurring if it takes longer than a second.

Once loaded you will see a typical browser form. Across the top of the page is a header bar with two buttons:

  1. Submit to OutPost
  2. Show Data Message

The Submit to OutPost button will submit the form data to OutPost to transmit as a packet radio message. It is disabled until the form is valid, with all required fields entered with acceptable values. The validity of the form as a whole is also indicated by the color of the header bar. When the entire form is valid the bar will turn from gray to green. Any field that is invalid either because no data has been entered or because the entered data is not acceptable is highlighted with a reddish glow. Depending on the browser, hovering the cursor over the field may give additional information about why the field is considered invalid.

The Show Data Message button will open an overlay with the current contents of the data message that would be transmitted to OutPost if the Submit to OutPost button were pressed. The underlying form is still active and the overlay will update in real-time as data is entered in form controls. The overlay is read-only so you can not type into it but you can select text and copy it using the clipboard. Click the button again to hide the overlay.

When the form is first loaded the cursor will be positioned at the first invalid field in form since this is typically the first field you'll want to enter. You can navigate between fields as usual using the mouse pointer and standard keyboard shortcuts.

Some form fields may be disabled with contents that looks like one or more words surrounded by curly braces. For example "{{date}}". These are placeholders that indicate values that will be automatically substituted when the form is submitted. If you show the data message content you will see that the placeholders are replaced in this output and continuously as you change the form. In this way the data message text always matches what you'd expect to see in OutPost.

Viewing Previously Entered Forms

If you have setup OutPost integration opening the message in OutPost should result in a new browser window containing the filled out message form. Since you are viewing the contents of a previously sent message the form controls are all read-only so that the data is not accidentally modified. The button bar has a blue color to give another visible clue that the form is being viewed rather than being created. The browser tab or window can be closed when viewing of the message is complete.

To manually view a previously entered form you must supply some additional data to the form through query parameters in the browser URL. There are two query parameters that matter, msgno and mode.

The msgno query parameter is used to refer to the data that is to be viewed. There must be a file in the msgs subdirectory of the installation with the name as the msgno parameter value. The form will load the data to be viewed from this file.

The mode parameter specifies the viewing mode. Currently, if it is not present the form will be editable and if it is present any value can be specified. If the value specified is readonly then the presentation mode will switch to the read-only view as described for the OutPost method of viewing messages above.

Note that pack-it-forms is used to replicate the paper forms used in the manual process and for ICS-213 derived forms the sender and receiver forms have different data in a few fields such as the various fields used for recording message numbers, the operate name/callsign, and the date/time the message was sent/received. Don't be surprised by this.

Creating New Forms

Forms for pack-it-forms are just normal HTML forms with some restrictions to allow the form to work smoothly with the Javscript code that implements pack-it-forms functionality. The simplest way to get started creating a new form is to copy an existing form and replace the content of the form element with the id the-form. With the exception of the title element in the document head, the rest of the HTML in the form outside this element is boilerplate required for the pack-it-forms Javascript and CSS to be able to display and process the forms correctly with the features described above.

In general, it shouldn't be necessary to create new forms completely from scratch, but should you wish to try to do so, the Explanation of the Form Boilerplate section below describes the purpose of the various boilerplate sections.

Assuming you start with all the boilerplate in place, here are the steps you should follow in creating your form:

  1. Change the title element in the document head
  2. Add input elements to the form
  3. Setup default and on-submit behavior on fields
  4. Adjust layout and styling

The next sections cover each of these in detail.

Change the Title Element in the Document Head

You should change the value of the title element to be the name of your new form; this will automatically be used both for the page title and for the form name header in the upper left hand side of the form.

Add Input Elements to the Form

To add fields to your form, you just need to add standard html input, select, and textarea elements --- just like any other HTML form. However, the input elements must contain a name attribute formatted like this:

  • If the element maps to a number in the form that you are trying to replicate, like 10, then the value should be that number followed by a period followed by a short description. Example: 10.subject. This means that the number will be used as the reference to the information in the PacFORMS output
  • Otherwise, just use a short, descriptive name like Method. Since the field name won't start with a number, this means that the whole text of the field name will be used as the reference in the PacFORMS output.

The select element is used when the user should pick from a set of known values. It isn't required, but is generally a good practice, to use the same content for the value attribute of the child option elements and the text that is used between the open and close tag of that option element. This ensures that anyone viewing the raw message text will see the value they expect.

Sometimes it is desirable to use a select elment for a pick list of common values and allow other arbitrary values to be used as well. This is supported by a pair of select and input elements of type text. The select element must have one option child element with a value attribute of "Other" and the text "Other:". The corresponding input element for arbitrary values must have the same name attribute as the select element with "-other" appened to it. It should be set to disabled by default. An example of this in the existing forms is the ICS Position field in the ics-header.html resource file.

While you can use different methods for adding descriptions to inputs, here are a few ways that generally work well with the default CSS:

  • If the control is a single control, it is a good idea to wrap it in a label element, with the text for the description preceding the actual input element.
  • If you are using something like a set of radio buttons that need to be grouped together, use the same scheme for each element but wrap them in a fieldset element with a legend element including the description for the entire set.
  • If the field is for a certain number of the form, putting a <span class="field-number"> that contains the number inside the label will make a small superscript number appear in the label at its position, similar to the way that field numbers are conveyed in the paper version of an ICS form.

If your form fits the ICS standards, you will need a large number of fields that contain information about the way that the form was transmitted and who it is going to/who it is from. pack-it-forms makes this easy to do: it is possible to include fragments of HTML from files in the resources/html directory. If you create a div element that has a data-include-html attribute in it, the element will be replaced with the contents of the first div element in the file resources/html/.html where signifies the value of the data-include-html attribute.

One thing that you may want to do with included HTML files is set the default values of included elements. You can do that by putting a JSON object that maps form field names to default values for those fields inside the

that will be replaced with the included content. The values are in the same format as the PacFORMS field values: a checkbox should have a value of CHECKED if it should be checked, and a collection of radiobuttons should have a value that matches one of the name attributes. Text fields can be set to a template, which will be expanded (see the next section).

If an input element represents a field that should have different values in a receiver's copy of a form than the senders, give the field the class no-msg-init which will prevent the senders field value (which is included in the message data) from being populated into the field for display. Use the template system (described in the next section) to substitute a different value for the receiver or the transmitter. The ics-header.html and ics-footer.html html fragments provide good examples of this.

Setup Default and On-submit Behavior on Fields

Default field values can be specified using the normal HTML form mechanisms. For text fields, however, there a template system provides additional flexibility in establishing the defaults.

Template expansion will be performed on the value attribute of all input elements with a type attribute value of "text" when the document is loaded. This will establish default values for form fields that the user can later edit.

The one exception to the expansion when the document is loaded is those elements with the class no-load-init, which prevents the expansion. Typically, these elements also have the class init-on-submit, which indicates that template expansion should occur at the time the form is submitted. In this case, when the form is initially displayed the template value will be shown in the field to provide an indication that something will be filled in later. Since these fields aren't usually intended to be edited by the user they usually have their disabled attribute set to "true".

Regular text in templates is copied from the template to the resulting string. The difference comes when placeholder values that are surrounded by double curly braces are encountered. To give an example, on January 1st, 2020, the template:

    The date is: {{date}}.

will result in the output text:

    The date is 01/20/2020.

This is the simplest possible template value, with just the name of the template to use. Some template types require additional information, in which case it can be supplied after the template name, separated by a colon. For example, if the query string of the document contains a msgno parameter with the value ABC001, then:

    The msgno is {{query-string:msgno}}.

will result in the output text:

    The msgno is ABC001.

Finally, the output of template expansion can be further modified by filters. Filters are separated from the template type by a vertical bar character. Filters can also take an argument separated by a colon. Assuming again that the date is January 1st, 2020, an example of a filter is:

    The month is: {{date|truncate:2}}

will result in the output text:

    The month is: 01

because "01" is the first two characters of the date string that would be substituted without the filter. Multiple filters can be chained together one after another, each separated by a vertical bar.

The following template types are available:

Name Argument Description
date none Current date string in "mm/dd/yyyy" format
time none Current local time string in hh:mm:ss format
msgno none Message number for this message as a string
selected-fields css-sel Get list of field values returned by css-sel
field field name Value of a field in the form
msg-field field name Value of a field in the received message
query-string key Value of query string parameter with name 'key'
envelope field name Value of !OUTPOST! envelope field
div-id id value Text content of the named div element
filename none Filename of the form (final name in URI path)
title none Title of the HTML document
expand-while-null templates Comma separated templates (, escapes)
open-brace none Insert a single '{' character
close-brace none Insert a single '}' character
open-tmpl none Insert a template open string ('{{')
close-tmpl none Insert a template close string ('}}')

The difference between field and msg-field is subtle but important. The field type retrieves the value of the form field with the given name. If the field exists in the form it will always get the current contents of that form element in the DOM. The msg-field type retrieves the value of a form field that was sent in a received message. When creating a new form, all msg-field fields will have a value that is the empty string. This distinction is important because some form fields have different values in the sender and receiver version of the form.

The following filters are available:

Name Argument Description
truncate length Truncate string to max of length characters
split fld delim Split into list by fld delim string
join separator Join list with separator between elements
remove value Remove elements matching value from list
sort type Sort list, if type is 'num', numeric, else text
re_search regexp Match regexp match, returning text or capture list
nth index Return the nth list item or character
trim none Remove whitespace at start and end of string
msgno2name msgno Expand message number to station
expandtmpl none Apply another layer of template expansion

You might also want to add some amount of validation to your custom form fields. pack-it-forms uses normal HTML5 form validation for validating fields: the default CSS provides a visual indication of which fields are invalid, and the top bar changes color depending on whether or not the form is fully valid. Here are a few tips to get you started with HTML5 form validation of this type:

  • If you have a field that must have some input in it, add the attribute required="true"
  • If the contents of the field has to be in a certain format, add a pattern attribute: the value should be a regular expression that will match values of the desired format.

Adjust Layout and Styling

Forms written using the above guidelines should be styled to look like paper forms, and to have a fairly responsive layout that will work with a large variety of screen sizes. However, if your form requires some specific styling, create the file resources/css/

.css and put any form-specific styling in it.

Explanation of the Form Boilerplate

If you wish to create a form completely from scratch this section describes the boilerplate in the standard forms and how it interacts with the pack-it-forms Javascript and CSS. With this information you can make choices about how much of this functionality you'd like to support in your form.

To do this we'll walk through the ICS213 form file and comment on each section.

<!DOCTYPE html>
    <meta http-equiv="Content-type" content="text/html;charset=UTF-8">

Standard HTML5 document start specifying a UTF-8 encoding.

    <link rel="stylesheet" type="text/css" href="resources/css/loading.css"/>

CSS that works with the div element with id "loading" that will be encountered shortly, to hide the rest of the form as all the form structure and contents are loaded.

    <link rel="stylesheet" type="text/css" href="resources/css/pack-it-forms.css"/>

CSS file that contains styles for the form interaction elements and that are likely to be useful in more than one form. This is highly recommended.

    <script type="text/javascript" src="resources/js/pack-it-forms.js"></script>

Javascript file that contains the Javascript code to implement the form behavior. This is required to have a functioning form.

    <title>ICS213: Message Form</title>


Completion of the normal HTML5 head section and start of the body section. An appropriate title should be specified for each form.

    <div id="loading"><div>Loading<div id="spin"><div id="spin_1" class="spin"></div></div></div></div>

Nested markup required to enable the animated loading progress bar without requiring any external graphics.

    <div id="err">
        <h1>Something went wrong.</h1>
        The following log information may help resolve the problem.
        <div id="error-log"></div>

Markup required for logging errors that occur during Javascript execution so that they can be presented to the user appropriately.

    <form id="the-form" name="the-form">

The actual from itself replaces the ellipses here. The Javascript requires that the id of the form have the value "the-form".

    <div data-include-html="outpost_message_header"></div>

An include reference that is replaced with data used to format the outpost message header. This is required for the Javascript to work properly. It should come after the form.

    <div data-include-html="submit-buttons"></div>

An include reference that is replaced with the submit buttons and related markup. This is required for the Javascript to work correctly. It should come after the form.


Standard HTML5 body and document close.