Global variables are those that are available throughout the length of the code, that is, these have no scope. The var keyword is used to declare a local variable or object. If the var keyword is omitted, a global variable is declared.

This’ keyword is used to point at the current object in the code. For instance: If the code is presently at an object created by the help of the ‘new’ keyword, then ‘this’ keyword will point to the object being created.

// for Single line comments and

/* Multi

Line

Comment

*/

To submit a form using JavaScript use document.form[0].submit();

document.form[0].submit();

‘ViewState’ is specific to a page in a session.

‘SessionState’ is specific to user specific data that can be accessed across all pages in the web application.

The status can be read as follows

alert(document.getElementById(‘checkbox1′).checked);

If the CheckBox will be checked, this alert will return TRUE.

Strict Mode adds certain compulsions to JavaScript. Under the strict mode, JavaScript shows errors for a piece of codes, which did not show an error before, but might be problematic and potentially unsafe. Strict mode also solves some mistakes that hamper the JavaScript engines to work efficiently.

Strict mode can be enabled by adding the string literal “use strict” above the file

Unshift method is like push method which works at the beginning of the array.  This method is used to prepend one or more elements to the beginning of the array.

Basic Groups Of Dataypes Are

• Reference types.
• Primitive