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Bookmarklets are one line scripts stored in the URL field of a bookmark. Bookmarklets have been around for a long time so they will work in older browsers.

JavaScript URI scheme[edit]

You should be familiar with URL that start with schemes like http and ftp, e.g. There is also the javascript scheme, which is used to start every bookmarklet.

javascript:alert("Hello, world!");

Using multiple lines of code[edit]

Since you cannot have line breaks in bookmarklets you must use a semicolon at the end of each code statement instead.

javascript:name=prompt("What is your name?");alert("Hello, "+name);

The javascript Protocol in Links[edit]

The javascript protocol can be used in links. This may be considered bad practice because it prevents access for or confuses users who have disabled JavaScript. See Best Practices.

<a href="javascript:document.bgColor='#0000FF'">blue background</a>


A large quantity of links may be found on, which show a variety of features that can be performed within Javascript.

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