HTML

Tables in HTML

tables are display method, some data need to be display in a grid view, this why we use tables in html.
using the table tag will create empty table, to add rows to table, use the tr tag (table row), where the td tag (table data) used to create table columns.
in order to add heading to the table, use the th tag (table heading), where you need to specify it scope attribute, which controls the display of headed of being column heading or row heading.
For Example the following code will display the marks o 3 student for 3 courses.

<!--Inside the body tag-->
<table>
    <tr>
      <th></th>
      <th scope="col">Math</th>
      <th scope="col">C++</th>
      <th scope="col">physics</th>
    </tr>
    <tr>
      <th scope="row">Ahmed</th>
      <td>85</td>
      <td>91</td>
      <td>71</td>
    </tr>

    <tr>
      <th scope="row">Rami</th>
      <td>95</td>
      <td>99</td>
      <td>94</td>
    </tr>

    <tr>
      <th scope="row">Anas</th>
      <td>74</td>
      <td>84</td>
      <td>65</td>
    </tr>
</table>

This will be the result:

	Math	C++	physics
Ahmed	85	91	71
Rami	95	99	94
Anas	74	84	65

some times some columns or rows require to be single cell and this can be achieved by using the colspan attribute with td or tr.

thead, tbody and tfoot are used in case of long tables to separate the heading of the table from the content and to show if there are any values in the footer of the tables.

JavaScript

JavaScript Objects and Constructors

another way to create an object is by using the object constructor notation rather than using the literal notation in javascript, this is done by using the new keyword then the Object constructor:

//create student object
var student = new Object();
//adding some properties to this object
student.name = 'Rami';
student.average = 96;

and to update an object property simply do the following:

student.average = 98;

what if we have more than one student in a class? which is true!
we can create object constructor that can creates as many as object we want:

function Student(name, average){
  //this keyword refers to the object
  //and this.name refers to the object property which is 'name'
  this.name = name;
  this.average = average;
}
//later we can use this function to create student objects as desired
var student1 = Student('Anas', 74.3);
var student2 = Student('Ahmed', 82.3);

Built-in JavaScripts Objects

1. Browser Object Model BOM
2. Document Object Model DOM
3. Global JavaScript Objects

In BOM there is the window object, which represented the current browser window or tab opened.
this objects container other objects that tell about the browser.
window.innerHeight is one of these objects that tells about the window height, and window.location refers to the current window url or file path.

In DOM there is the document object, which is a tree of html page tags, this object allow javascipt to access, modify and update the html structure from with javascripts.
one of the methods of the document object is documentgetElementById(‘tagId’), which points to the element that has that id within parenthesis.

Global Javascript Objects such as string which has many methods and properties within like length property which tells how long the string is, toUpperCase() method which converts a string to upper case letters. and all the other data types along with the string are global javascript objects.
another example of the global objects of javascript is the Math object, this objects contains all the necessary methods and properties for using in case.
property example is Math.pi, which return the value of pi in decimal.
method example is Math.random(), which generates a random number between 0 and 1.