phpMan > man > HTML::Form(3pm)

NAME
    HTML::Form - Class that represents an HTML form element

VERSION
    version 6.07

SYNOPSIS
     use HTML::Form;
     $form = HTML::Form->parse($html, $base_uri);
     $form->value(query => "Perl");

     use LWP::UserAgent;
     $ua = LWP::UserAgent->new;
     $response = $ua->request($form->click);

DESCRIPTION
    Objects of the "HTML::Form" class represents a single HTML "<form> ... </form>" instance. A form
    consists of a sequence of inputs that usually have names, and which can take on various values.
    The state of a form can be tweaked and it can then be asked to provide HTTP::Request objects
    that can be passed to the request() method of LWP::UserAgent.

    The following methods are available:

    @forms = HTML::Form->parse( $html_document, $base_uri )
    @forms = HTML::Form->parse( $html_document, base => $base_uri, %opt )
    @forms = HTML::Form->parse( $response, %opt )
        The parse() class method will parse an HTML document and build up "HTML::Form" objects for
        each <form> element found. If called in scalar context only returns the first <form>.
        Returns an empty list if there are no forms to be found.

        The required arguments is the HTML document to parse ($html_document) and the URI used to
        retrieve the document ($base_uri). The base URI is needed to resolve relative action URIs.
        The provided HTML document should be a Unicode string (or US-ASCII).

        By default HTML::Form assumes that the original document was UTF-8 encoded and thus encode
        forms that don't specify an explicit *accept-charset* as UTF-8. The charset assumed can be
        overridden by providing the "charset" option to parse(). It's a good idea to be explicit
        about this parameter as well, thus the recommended simplest invocation becomes:

            my @forms = HTML::Form->parse(
                Encode::decode($encoding, $html_document_bytes),
                base => $base_uri,
                charset => $encoding,
            );

        If the document was retrieved with LWP then the response object provide methods to obtain a
        proper value for "base" and "charset":

            my $ua = LWP::UserAgent->new;
            my $response = $ua->get("http://www.example.com/form.html");
            my @forms = HTML::Form->parse($response->decoded_content,
                base => $response->base,
                charset => $response->content_charset,
            );

        In fact, the parse() method can parse from an HTTP::Response object directly, so the example
        above can be more conveniently written as:

            my $ua = LWP::UserAgent->new;
            my $response = $ua->get("http://www.example.com/form.html");
            my @forms = HTML::Form->parse($response);

        Note that any object that implements a decoded_content(), base() and content_charset()
        method with similar behaviour as HTTP::Response will do.

        Additional options might be passed in to control how the parse method behaves. The following
        are all the options currently recognized:

        "base => $uri"
            This is the URI used to retrieve the original document. This option is not optional ;-)

        "charset => $str"
            Specify what charset the original document was encoded in. This is used as the default
            for accept_charset. If not provided this defaults to "UTF-8".

        "verbose => $bool"
            Warn (print messages to STDERR) about any bad HTML form constructs found. You can trap
            these with $SIG{__WARN__}. The default is not to issue warnings.

        "strict => $bool"
            Initialize any form objects with the given strict attribute. If the strict is turned on
            the methods that change values of the form will croak if you try to set illegal values
            or modify readonly fields. The default is not to be strict.

    $form->push_input( $type, \%attr, $verbose )
        This method adds additional inputs to the form. The first argument is the type of input
        (e.g. hidden, option, etc.). The second argument is a reference to a hash of the input
        attributes. The third argument is optional, and will issue warnings about unknown input
        types.

        Example:

            push_input( 'hidden', {
                name  => 'NewFormElement',
                id    => 'NewFormElementId',
                value => 'some value',
            });

    $method = $form->method
    $form->method( $new_method )
        This method is gets/sets the *method* name used for the HTTP::Request generated. It is a
        string like "GET" or "POST".

    $action = $form->action
    $form->action( $new_action )
        This method gets/sets the URI which we want to apply the request *method* to.

    $enctype = $form->enctype
    $form->enctype( $new_enctype )
        This method gets/sets the encoding type for the form data. It is a string like
        "application/x-www-form-urlencoded" or "multipart/form-data".

    $accept = $form->accept_charset
    $form->accept_charset( $new_accept )
        This method gets/sets the list of charset encodings that the server processing the form
        accepts. Current implementation supports only one-element lists. Default value is "UNKNOWN"
        which we interpret as a request to use document charset as specified by the 'charset'
        parameter of the parse() method.

    $value = $form->attr( $name )
    $form->attr( $name, $new_value )
        This method give access to the original HTML attributes of the <form> tag. The $name should
        always be passed in lower case.

        Example:

           @f = HTML::Form->parse( $html, $foo );
           @f = grep $_->attr("id") eq "foo", @f;
           die "No form named 'foo' found" unless @f;
           $foo = shift @f;

    $bool = $form->strict
    $form->strict( $bool )
        Gets/sets the strict attribute of a form. If the strict is turned on the methods that change
        values of the form will croak if you try to set illegal values or modify readonly fields.
        The default is not to be strict.

    @inputs = $form->inputs
        This method returns the list of inputs in the form. If called in scalar context it returns
        the number of inputs contained in the form. See "INPUTS" for what methods are available for
        the input objects returned.

    $input = $form->find_input( $selector )
    $input = $form->find_input( $selector, $type )
    $input = $form->find_input( $selector, $type, $index )
    @inputs = $form->find_input( $selector )
    @inputs = $form->find_input( $selector, $type )
        This method is used to locate specific inputs within the form. All inputs that match the
        arguments given are returned. In scalar context only the first is returned, or "undef" if
        none match.

        If $selector is not "undef", then the input's name, id, class attribute must match. A
        selector prefixed with '#' must match the id attribute of the input. A selector prefixed
        with '.' matches the class attribute. A selector prefixed with '^' or with no prefix matches
        the name attribute.

        If $type is not "undef", then the input must have the specified type. The following type
        names are used: "text", "password", "hidden", "textarea", "file", "image", "submit",
        "radio", "checkbox" and "option".

        The $index is the sequence number of the input matched where 1 is the first. If combined
        with $name and/or $type, then it selects the *n*th input with the given name and/or type.

    $value = $form->value( $selector )
    $form->value( $selector, $new_value )
        The value() method can be used to get/set the value of some input. If strict is enabled and
        no input has the indicated name, then this method will croak.

        If multiple inputs have the same name, only the first one will be affected.

        The call:

            $form->value('foo')

        is basically a short-hand for:

            $form->find_input('foo')->value;

    @names = $form->param
    @values = $form->param( $name )
    $form->param( $name, $value, ... )
    $form->param( $name, \@values )
        Alternative interface to examining and setting the values of the form.

        If called without arguments then it returns the names of all the inputs in the form. The
        names will not repeat even if multiple inputs have the same name. In scalar context the
        number of different names is returned.

        If called with a single argument then it returns the value or values of inputs with the
        given name. If called in scalar context only the first value is returned. If no input exists
        with the given name, then "undef" is returned.

        If called with 2 or more arguments then it will set values of the named inputs. This form
        will croak if no inputs have the given name or if any of the values provided does not fit.
        Values can also be provided as a reference to an array. This form will allow unsetting all
        values with the given name as well.

        This interface resembles that of the param() function of the CGI module.

    $form->try_others( \&callback )
        This method will iterate over all permutations of unvisited enumerated values (<select>,
        <radio>, <checkbox>) and invoke the callback for each. The callback is passed the $form as
        argument. The return value from the callback is ignored and the try_others() method itself
        does not return anything.

    $request = $form->make_request
        Will return an HTTP::Request object that reflects the current setting of the form. You might
        want to use the click() method instead.

    $request = $form->click
    $request = $form->click( $selector )
    $request = $form->click( $x, $y )
    $request = $form->click( $selector, $x, $y )
        Will "click" on the first clickable input (which will be of type "submit" or "image"). The
        result of clicking is an HTTP::Request object that can then be passed to LWP::UserAgent if
        you want to obtain the server response.

        If a $selector is specified, we will click on the first clickable input matching the
        selector, and the method will croak if no matching clickable input is found. If $selector is
        *not* specified, then it is ok if the form contains no clickable inputs. In this case the
        click() method returns the same request as the make_request() method would do. See
        description of the find_input() method above for how the $selector is specified.

        If there are multiple clickable inputs with the same name, then there is no way to get the
        click() method of the "HTML::Form" to click on any but the first. If you need this you would
        have to locate the input with find_input() and invoke the click() method on the given input
        yourself.

        A click coordinate pair can also be provided, but this only makes a difference if you
        clicked on an image. The default coordinate is (1,1). The upper-left corner of the image is
        (0,0), but some badly coded CGI scripts are known to not recognize this. Therefore (1,1) was
        selected as a safer default.

    @kw = $form->form
        Returns the current setting as a sequence of key/value pairs. Note that keys might be
        repeated, which means that some values might be lost if the return values are assigned to a
        hash.

        In scalar context this method returns the number of key/value pairs generated.

    $form->dump
        Returns a textual representation of current state of the form. Mainly useful for debugging.
        If called in void context, then the dump is printed on STDERR.

INPUTS
    An "HTML::Form" objects contains a sequence of *inputs*. References to the inputs can be
    obtained with the $form->inputs or $form->find_input methods.

    Note that there is *not* a one-to-one correspondence between input *objects* and <input>
    *elements* in the HTML document. An input object basically represents a name/value pair, so when
    multiple HTML elements contribute to the same name/value pair in the submitted form they are
    combined.

    The input elements that are mapped one-to-one are "text", "textarea", "password", "hidden",
    "file", "image", "submit" and "checkbox". For the "radio" and "option" inputs the story is not
    as simple: All <input type="radio"> elements with the same name will contribute to the same
    input radio object. The number of radio input objects will be the same as the number of distinct
    names used for the <input type="radio"> elements. For a <select> element without the "multiple"
    attribute there will be one input object of type of "option". For a <select multiple> element
    there will be one input object for each contained <option> element. Each one of these option
    objects will have the same name.

    The following methods are available for the *input* objects:

    $input->type
        Returns the type of this input. The type is one of the following strings: "text",
        "password", "hidden", "textarea", "file", "image", "submit", "radio", "checkbox" or
        "option".

    $name = $input->name
    $input->name( $new_name )
        This method can be used to get/set the current name of the input.

    $input->id
    $input->class
        These methods can be used to get/set the current id or class attribute for the input.

    $input->selected( $selector )
        Returns TRUE if the given selector matched the input. See the description of the
        find_input() method above for a description of the selector syntax.

    $value = $input->value
    $input->value( $new_value )
        This method can be used to get/set the current value of an input.

        If strict is enabled and the input only can take an enumerated list of values, then it is an
        error to try to set it to something else and the method will croak if you try.

        You will also be able to set the value of read-only inputs, but a warning will be generated
        if running under "perl -w".

    $autocomplete = $input->autocomplete
    $input->autocomplete( $new_autocomplete )
        This method can be used to get/set the current value (if any) of "autcomplete" for the
        input.

    $input->possible_values
        Returns a list of all values that an input can take. For inputs that do not have discrete
        values, this returns an empty list.

    $input->other_possible_values
        Returns a list of all values not tried yet.

    $input->value_names
        For some inputs the values can have names that are different from the values themselves. The
        number of names returned by this method will match the number of values reported by
        $input->possible_values.

        When setting values using the value() method it is also possible to use the value names in
        place of the value itself.

    $bool = $input->readonly
    $input->readonly( $bool )
        This method is used to get/set the value of the readonly attribute. You are allowed to
        modify the value of readonly inputs, but setting the value will generate some noise when
        warnings are enabled. Hidden fields always start out readonly.

    $bool = $input->disabled
    $input->disabled( $bool )
        This method is used to get/set the value of the disabled attribute. Disabled inputs do not
        contribute any key/value pairs for the form value.

    $input->form_name_value
        Returns a (possible empty) list of key/value pairs that should be incorporated in the form
        value from this input.

    $input->check
        Some input types represent toggles that can be turned on/off. This includes "checkbox" and
        "option" inputs. Calling this method turns this input on without having to know the value
        name. If the input is already on, then nothing happens.

        This has the same effect as:

            $input->value($input->possible_values[1]);

        The input can be turned off with:

            $input->value(undef);

    $input->click($form, $x, $y)
        Some input types (currently "submit" buttons and "images") can be clicked to submit the
        form. The click() method returns the corresponding HTTP::Request object.

    If the input is of type "file", then it has these additional methods:

    $input->file
        This is just an alias for the value() method. It sets the filename to read data from.

        For security reasons this field will never be initialized from the parsing of a form. This
        prevents the server from triggering stealth uploads of arbitrary files from the client
        machine.

    $filename = $input->filename
    $input->filename( $new_filename )
        This get/sets the filename reported to the server during file upload. This attribute
        defaults to the value reported by the file() method.

    $content = $input->content
    $input->content( $new_content )
        This get/sets the file content provided to the server during file upload. This method can be
        used if you do not want the content to be read from an actual file.

    @headers = $input->headers
    input->headers($key => $value, .... )
        This get/set additional header fields describing the file uploaded. This can for instance be
        used to set the "Content-Type" reported for the file.

SEE ALSO
    LWP, LWP::UserAgent, HTML::Parser

AUTHOR
    Gisle Aas <gisle AT activestate.com>

COPYRIGHT AND LICENSE
    This software is copyright (c) 1998 by Gisle Aas.

    This is free software; you can redistribute it and/or modify it under the same terms as the Perl
    5 programming language system itself.