How to print document in javascript? or How to show print dialog box in javascript?

Definition: 

window.print() Method

Using window.print() to print a document

The JavaScript syntax used to simulate the print button currently only works in all modern browsers, so it can be a valid substitute inside a browser window where the toolbar is disabled.

Syntax used to print a document:

window.print()

Example:

<input type="button" value="Print this page" onClick="window.print()">

OR

Another way to accomplish the exact same task as above is to use a "JavaScript url". A JavaScript url is a special kind of url that executes a command, instead of loading the specified url.

<a href="javascript:window.print()"><img src="../images/print.gif"></a>

Output:

You can see print dialogue box.