CodeIgniter Form Building and Validation Made Easy

CodeIgniter makes building and validating forms a breeze.

You can create a form in CodeIgniter using the form helper, which provides a simple way to generate HTML form elements.

The form validation process in CodeIgniter is based on a set of rules that you define for each field in the form.

These rules can be used to check if the form data is valid, and if not, display error messages to the user.

CodeIgniter's form validation class comes with a range of built-in rules, including required, email, and numeric.

You can also create your own custom validation rules using the form validation class.

CodeIgniter's form helper functions make creating forms a breeze. They allow you to create forms that are portable, meaning they can adapt to changes in your URLs.

The form_open() function is a great example of this. It creates an opening form tag with a base URL built from your config preferences, adding the attribute accept-charset based on the charset value in your config file.

This function also permits you to add form attributes and hidden input fields, making it a convenient and efficient way to create forms.

Escaping Field Values is a crucial aspect of form creation, and there are several functions that can help you achieve this safely. You may need to use HTML and characters such as quotes within your form elements, which can cause the form to break if not handled properly.

The common function html_escape() is one such function that converts HTML special characters so that they can be used safely. This is especially useful when creating your own form elements, as the form helper functions listed on this page will automatically escape the form values.

Attributes can be added by passing an associative array to the second parameter of the function. For example, you can use the function to add a hidden input field to your form.

You can also use the esc() function to escape field values, which is similar to html_escape(). However, the esc() function is used when you pass values as strings, whereas html_escape() is used when passing values as associative arrays.

It's worth noting that if you use any of the form helper functions listed on this page, the form values will be automatically escaped, so there is no need to call these functions. However, if you are creating your own form elements, you may need to use these functions to ensure that your form values are escaped safely.

Here are some examples of how to use the html_escape() and esc() functions:

The form_prep function is another way to safely use HTML and characters within form elements. It converts HTML so that it can be used safely, and is especially useful when creating your own form elements.

Form Helper Functions are a breeze to use, and one of the key benefits is that they make your site more portable in case your URLs ever change.

The form_open() function creates an opening form tag with a base URL built from your config preferences. You can also add form attributes and hidden input fields.

This function is super useful because it saves you from hard-coding your own HTML, which can be a real pain.

You can add attributes to the form_open() function by passing an associative array to the second parameter. This allows you to customize the form as needed.

For example, if you want to add a name attribute to the form, you can pass an associative array with the key 'name' set to the desired value.

If you need to upload files with the form, you'll want to use the form_open_multipart() function instead. This function is identical to form_open() except that it adds a multipart attribute.

The form_submit() function lets you generate a standard submit button. You can customize the button by passing an associative array to the first parameter.

You can also add extra data to the form, like JavaScript, using the third parameter of the form_submit() function.

Adding Hidden Input Fields is a common need when working with forms. To do this, you can pass an associative array to the third parameter.

You can add multiple hidden input fields by submitting an associative array. This allows you to create fields with different names and values.

To create a single hidden input field, you can submit a name/value string. This is a more straightforward approach.

The form_hidden() function can be used to generate hidden input fields.

Password() is a function that's similar to form_input(), but with a key difference - it sets the input type as "password".

This means that any text entered into a password field will be hidden from view, making it a more secure option for users to enter sensitive information.

The reset button is a crucial part of any form, allowing users to start fresh and try again.

You can generate a standard reset button using the form_reset() function, which works identically to form_submit(). I've found this to be particularly useful when users need to clear out previous entries.

The form_reset() function is simple to use and can be a lifesaver for users who need to start over.

The "Prep" section of our form helper functions is where things get interesting. You can use the form_prep() function to safely use HTML and characters within form elements without breaking out of the form.

This function is especially useful when you're creating your own form elements, as it converts HTML so that it can be used safely. For example, if you have a string with a set of quotes, it will cause the form to break, but the form_prep function can fix that.

The form_prep function is also important to note that if you use any of the form helper functions listed in this page, the form values will be prepped automatically, so there is no need to call this function.

Setting the value of a form field is a straightforward process. You can use the set_value() function to do this.

To use set_value(), you must supply the field name as the first parameter of the function. This parameter is required.

The second parameter of the set_value() function allows you to set a default value for the form. If you don't supply a second parameter, the form will show a blank value when loaded.

For example, if you want a form field to show "0" when loaded for the first time, you can use the set_value() function like this:

Form Input Fields are a crucial part of any web form, and CodeIgniter makes it easy to create them.

You can generate a standard text input field with just a field name and value, passed in as the first and second parameters of the form_input() function.

If you need to include additional data in your form, such as JavaScript, you can pass it as a string in the third parameter.

Hidden fields can be added by passing an associative array to the third parameter. This allows you to create multiple fields at once.

You can submit a name/value string to form_hidden() to create one field. This is a straightforward way to add a single hidden field to your form.

However, if you need to add multiple hidden fields, you can submit an associative array to form_hidden(). This is a more efficient way to add multiple fields with different names and values.

You can generate a standard text input field using the form_input() function. This function allows you to pass the field name and value in the first and second parameters.

The form_input() function can also accept an associative array containing any data you wish your form to contain. This is a convenient way to add extra information to your form.

If you need to pass additional data like JavaScript, you can include it as a string in the third parameter.

Textarea is a type of form input field that's similar to the input field, but with a few key differences. It's generated by the form_textarea() function.

You can specify the number of rows and columns in a textarea using the "rows" and "cols" attributes, instead of "maxlength" and "size" like you would with an input field.

You can use the form_fieldset() function to generate fieldset/legend fields in your forms. This function is similar to others, allowing you to submit an associative array in the second parameter to set additional attributes.

The form_fieldset() function takes two parameters: the first is the legend text, and the second is an optional array of attributes.

You can set attributes like id and class using an associative array, as shown in the example where the id is set to 'address_info' and the class is set to 'address_info'.

The function will produce a fieldset with an id and class, a legend with the provided text, and any additional content you specify.

A fieldset can be closed using the form_fieldset_close() function, which will produce a closing tag for the fieldset.

Checkbox fields are a great way to collect user input, and they're relatively easy to use. You can generate a checkbox field with the form_checkbox() function, which takes three parameters: the name of the checkbox, the value of the checkbox, and a boolean to determine whether the box should be checked or not.

For example, if you want a checkbox to be checked by default, you can pass TRUE as the third parameter. You can also pass an array of attributes to the function to customize the checkbox field.

To display a checkbox in the state it was submitted, you can use the set_checkbox() function, which takes three parameters: the name of the checkbox, its value, and an optional default value.

You can set the value of an input form or textarea using the set_value() function, which requires the field name as its first parameter. This function is especially useful for setting default values for forms.

To set a default value, you can pass it as the second parameter of the set_value() function. For instance, if you have a form with a field named "quantity" and you want it to show "0" when loaded for the first time, you can use set_value('quantity', '0').

Multiselect fields are a great way to let users select multiple options from a list. You can create a standard multiselect field using the form_multiselect() function.

The first parameter of form_multiselect() is the name of the field, which needs to use POST array syntax, like "foo[]". This is because multiselect fields allow users to select multiple options.

The second parameter is an associative array of options, which is similar to the options array used in form_dropdown(). You can use this to define the list of options users can choose from.

The third parameter is the value or values you wish to be selected. This is where you specify which options should be pre-selected when the form is loaded.

In practice, I've found that using form_multiselect() can be a bit tricky, but with the right syntax and parameters, it's a powerful tool for creating flexible and user-friendly forms.

Set Select is a function that lets you display the selected item in a select menu. It requires three parameters: the name of the select menu, the value of each item, and an optional parameter to set a default item.

The first parameter, the name of the select menu, is crucial as it identifies the specific menu being referenced. For example, if you have multiple select menus on a single form, you'll need to specify each one individually.

You can use the second parameter to specify the value of each item in the select menu. This is usually done when you want to pre-select an item or dynamically update the menu based on user input.

The third parameter, optional as it may be, allows you to set an item as the default selection. This is done using boolean TRUE/FALSE, where TRUE sets the item as the default and FALSE leaves it as is.

When working with forms in CodeIgniter, it's essential to use the built-in helper functions to fetch data, rather than relying on direct access to the $_POST, $_GET, $_COOKIE, or $_SERVER arrays.

These helper functions, such as $this->input->post(), $this->input->get(), $this->input->cookie(), and $this->input->server(), will check if the item is set and return NULL if not, saving you the hassle of testing whether an item exists first.

Here are the main benefits of using these helper functions:

The upload feature is a crucial part of any form, allowing users to share files with the site.

Form_upload() is a function that enables file uploads, making it identical to form_input() except for its file type setting.

If you need to allow users to upload files, form_upload() is the way to go, as it's specifically designed for this purpose.

To use form_upload(), simply call the function and set it as a "file" type, just like form_input(), but with the added functionality of file uploads.

This function is a must-have for any form that requires users to share files, and it's surprisingly easy to implement.

The Validation Rule Reference is a crucial part of the Form Helper Functions, providing a list of native rules to validate form elements.

The following rules are available to use:

HTTP Request Methods are a breeze with CodeIgniter's helper methods. You can fetch POST, GET, COOKIE, or SERVER items with ease.

Using these methods has a significant advantage: they check if the item is set and return NULL if not, saving you the trouble of testing whether an item exists first. This means you can use data without having to worry about its existence.

The methods are easy to use: simply call them like this: $this->input->post(), $this->input->get(), $this->input->cookie(), or $this->input->server().

Here's a quick rundown of the parameters and return types for each method: