JavaScript Interview Questions and Answers (294) - Page 12

By using document.getElementById("id").disable = true we can disable the Html objects.

If a variable with no value is undefined that means the variable has not been initialized.
If the variable initialized with empty value, that is null.

To get the contents of input box in java script we are using below sentence.

var content =Window.document.getElementById("inputBox Id").value;

NOTE: This is objective type question, Please click question title for correct answer.

NOTE: This is objective type question, Please click question title for correct answer.

With the help of Document object model,JavaScript creates dynamic HTML.

JavaScript can change all the HTML elements on the page.
JavaScript can change all the HTML attributes in the page.
JavaScript can change all the CSS styles in the page.
JavaScript can remove existing HTML elements and attributes.
JavaScript can add new HTML elements and attributes.
JavaScript can react to all existing HTML events in the page.
JavaScript can create new HTML events in the page.

VB.Net

link.Attributes("onClick") = "window.open('url','name','properties')"

C#

link.Attributes["onClick"] = "window.open('url','name','properties')";

Use the fullscreen features of windows open method .It has yes and no option .Use below code:-

Button2.Attributes.Add("onclick", "window.open('Default2.aspx','','fullscreen=yes')");

Actually we can not check using Javascript if the browser is configured to use Javascript because obviously it can not run.
So instead we can use a <noscript> tag.<noscript> tag will always appear when Javascript is not supported
and therefore we can put information within this tag to warn the user to enable Javascript on their browser.
For Example:-

<noscript>

  ......

</noscript>

If app is an angular module,
calling order is
app.config()
app.run()
directive's compile functions (if they are found in the dom)
app.controller()
directive's link functions (again if found)

Write below code:-

var table_rows_cnt = document.getElementById('your_table_id').getElementsByTagName("tr").length;

alert(table_rows_cnt);

Or you can also write:-

var table_rows_cnt = document.getElementById('your_table_id').rows.length;

alert(table_rows_cnt);

We can write below code:-

var table_rows_cnt = document.getElementById('your_table_id').getElementsByTagName('tbody')[0].getElementsByTagName('tr').length;

alert(table_rows_cnt);

The typeof operator is an in-built operator and is used to identify the type of an object.
It always returns a String value,so we should always compare return value to a string.
typeof is an operand and not a function.

typeof 25;        

Output :- number

typeof true;      

Output :- boolean

typeof undefined; 

Output :- undefined

typeof {};        

Output :- object