What does this mean in documentation: square bracket followed by comma ( [, )

Question 1

Today this caught my attention on jQuery's API Documentation for the closest selector:

.closest( selector [, context ] )

What exactly does [, context] mean? I know I can put a variable or jQuery object there to set as the context. This itself isn't entirely clear to me, but the part in particular I'm asking about today is the square bracket comma ( [, ). What does this mean? I've also seen similar notation on php.net's manual pages.

bool ob_start ([ callable $output_callback [, int $chunk_size = 0 [, ...

Is there some preliminary lesson I've missed? because this is greek to me and I can't be the only one who's looked at this and thought "WTF..." but ignored it and went on guessing, when I could have saved a lot of time...

Question 2

It means that parameter is optional. You don't have to provide it and if you don't it will use the value you see listed there by default.

Question 3

*Updated to include all of the fields you are editing

It sounds like you have the right idea. You would probably want to create a new div on your page for the edit modal dialog.

<div id="dialog-edit" style="background-color:#CCC;display:none;">
    <input type="hidden" id="editLinkId" value="" />
    Link Name: <input type="text" id="txtLinkTitle" class="text" />
    Link Description <input type="text" id="txtLinkDescription" class="text" />
    Link URL <input type="text" id="txtLinkURL" class="text" />
</div>

When the user clicks your edit button you'll want to populate the hidden field and the text box with the values of the link they clicked on and then turn the dialog on.

$('.edit').click(function () {
            //populate the fields in the edit dialog. 
            var parent = $(this).closest('div');
            var id = parent.attr('id');

            $("#editLinkId").val(id);

            //get the title field
            var title = $(parent).find('.linkHeader').html();
            var description = $(parent).find('.linkDescription p').html();
            var url = $(parent).find('.linkDescription span a').attr("href");
            $("#txtLinkTitle").val(title);
            $("#txtLinkDescription").val(description);
            $("#txtLinkURL").val(url);

            $("#dialog-edit").dialog({
                bgiframe: true,
                autoOpen: false,
                width: 400,
                height: 400,
                modal: true,
                title: 'Update Link',
                buttons: {
                    'Update link': function () {
                        //code to update link goes here...most likely an ajax call.

                        var linkID = $("#linkID").val();
                        var linkTitle = $("#txtLinkTitle").val()
                        var linkDescription = $("#txtLinkDescription").val()
                        var linkURL = $("#txtLinkURL").val()
                        $.ajax({
                            type: "GET",
                            url: "ajax_calls.php?function=updateLink&linkID=" + linkID + "&linkTitle=" + linkTitle + "&linkDescription=" + linkDescription + "&linkURL=" + linkURL,
                            dataType: "text",
                            error: function (request, status, error) {
                                alert("An error occured while trying to complete your request: " + error);
                            },
                            success: function (msg) {
                                //success, do something 
                            },
                            complete: function () {
                                //do whatever you want 
                            }
                        }); //end ajax
                        //close dialog
                        $(this).dialog('close');
                    },
                    Cancel: function () {
                        $(this).dialog('close');
                    }
                },
                close: function () {
                    $(this).dialog("destroy");
                }
            }); //end .dialog()

            $("#dialog-edit").show();
            $("#dialog-edit").dialog("open");

        }) //end edit click

Question 4

this (in the context of a module) is the same as exports in node.js. However you should generally use exports/module.exports instead, so that it's explicitly clear what you're modifying.

Question 5

They're known as generics in java, and templates in C++.

http://java.sun.com/developer/technicalArticles/J2SE/generics/

Question 6

i think your problem may be in ajax code since you are using formData object . try append the message variable with it

$('#submit').on('click', function(){

  var fd = new FormData(this);
  fd.append('file',$('#file')[0].files[0]);
  fd.append('message ',$('#message').val());

  $.ajax({
    method:"POST",
    url:"<?php echo site_url('home/send_chat');?>",    
    data: fd,  
    cache: false,
    contentType: false,
    processData: false,   
    success: function(data){                 
      alert(data);
    },
    error: function(xhr, status, error) {
      alert(xhr.responseText);
    }  
  });
});

What does this mean in documentation: square bracket followed by comma ( [, )

Answers

php,jquery