Understanding jQuery function - Comment box

Hi guys
We are making a comment box using jquery, but we don’t quite understand the the code in detail. Can anyone of you please help us? I have marked what we find most difficult in bold.

I’m sorry that the code is so long, but I figured that it would be easier to get the connection and understand the code.


/* JQuery used for comment box functions
document ready function - Jquery detects that the page status is ready
code will ony run once page is ready for javascript code to execute
Jquery is a javascript library - simplifies the language and event handling
*/

class CommentBox{

constructor(username, comment){
this.username = username;
this.comment = comment;
}
}
// The preventDefault will prevent the default event from occuring. The preventDefault shares similar features to the return false in JavaScript
(document).ready(function(){ (".editor-header a").click(function(e){
e.preventDefault();

**// We create a dialog box. **
var _val = (this).data("role"),** **_sizeValIn = parseInt((this).data(“size-val”) + 1),
_sizeValRe = parseInt((this).data("size-val") - 1),** **_size = (this).data(“size”);
if(_size == “in-size”){
document.execCommand(_val, false, _sizeValIn + “px”);
} else{
document.execCommand(_val, false, _sizeValRe + “px”);
}
});
});

// Universal function to retrieve user Array from LocalStorage
var activeUser = JSON.parse(localStorage.getItem(‘activeUser’))

var username = activeUser.username

// Define comment

if(localStorage.getItem(‘comments’) == null) {
var comments = ;
} else {
var comments = JSON.parse(localStorage.getItem(‘comments’));

}

// below - pulls in html div’s - clarify how
$(document).ready(function(){
var text = ("#text"),
submit = (“input[type=‘submit’]”),
listComment = (".listComments"),
loading = (".loading"),
_data,
totalCom = (".total-comment");

$totalCom.text($(".listComments > div").length);

$($submit).click(function(){
if($text.html() == “”){
alert(“Please write a comment!”);
$text.focus();
} else{
_data = $text.html();

return false;

}

});
});

$(document).ready(function(){
var text = ("#text"),
submit = (“input[type=‘submit’]”),
listComment = (".listComments"),
loading = (".loading"),
_data,
totalCom = (".total-comment");

totalCom.text((".listComments > div").length);

$($submit).click(function() {
  if ($text.html() == "") {
  
  $text.focus();
} else {
  _data = $text.html();
  comment = _data;

comment = new CommentBox(username, comment);
comments.push(comment);
localStorage.setItem(‘comments’, JSON.stringify(comments));

$loading.show().fadeOut(300);
$listComment.append("

" + _data + “
”);
$text.html("");
totalCom.text((".listComments > div").length);

return false;
}

// Show activeUsers previous comments on mainpage

});
var allcomments = JSON.parse(localStorage.getItem(‘comments’));
var user = JSON.parse(localStorage.getItem(‘activeUser’));
for(i=0; i < allcomments.length; i++){
if(user.username == allcomments[i].username) {

var listComment = (".listComments")

$loading.show().fadeOut(300);
$listComment.append("

" + allcomments[i].comment + “
”);
$text.html("");

}
}
});

To be honest, i also did not know about the details of this code. In fact, these terms are quite new to me. And students can get help from edubirdie reviews to write their task easily. So, if any one knows about this term then do share it with me also. I will be very thankful to you.