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# Develop menu

The Develop menu provides tools for web developers creating websites for Safari and Mac OS X.

Note:If the Develop menu does not appear in the menu bar, open Safari preferences, click Advanced, and select “Show Develop menu in menu bar.”

Option
Description

Open Page With

Lets you open the displayed webpage using a different web browser on your computer. All web browsers on your computer are listed in the submenu.

User Agent

Lets you change how your web browser is identified by the web server. Use this option to “spoof” the web server into thinking that you’re using a different browser, operating system, or version of Safari, so you can investigate whether the server is providing different content under varying conditions.

Show Web Inspector

Opens the Web Inspector. The Web Inspector lists the resources found on a webpage, such as documents, style sheets, and scripts. It lets you view and search the page’s source code, Cascading Style Sheet (CSS) information, DOM trees, visual DOM metrics, and DOM properties. The Web Inspector also contains an error console and network timeline.

Show Error Console

Opens the Web Inspector’s error console, which displays HTML and XML syntax errors and warnings. The error console also displays JavaScript errors and other messages from console.log, console.error, console.warn, console.assert, and console.info.

Show Snippet Editor

Opens a window you can use to quickly test small fragments of HTML without opening an entire webpage.

Show Extension Builder

Opens the Extension Builder, a tool used by developers to package and provide metadata for extensions they create.

Start Debugging JavaScript

Opens the Web Inspector and turns on script debugging.

Start Profiling JavaScript

Starts recording a profile of any JavaScript scripts being run by the current webpage. To view the recorded profile, click Stop Profiling JavaScript.

Disable Caches

Causes Safari to retrieve a subresource from the web server each time the subresource is accessed, rather than using a cached copy.

Disable Images

Causes Safari to show the alternate content for images instead of the images themselves. This is useful for making sure your webpage has appropriate alternate content. Deselecting “Display images when the page opens” in the Safari Appearance preferences pane has the same affect.

Disable Styles

Causes Safari to ignore all Cascading Style Sheet (CSS) styles. This is useful for investigating some types of page layout problems on your website. If you have a style sheet set in the Advanced pane of Safari preferences, it continues to be used.

Disable JavaScript

Causes Safari to ignore all JavaScript. This is useful for investigating certain problems with how parts of websites behave, and for testing how a website performs on web browsers that don’t support JavaScript or have JavaScript disabled. You can also turn JavaScript off and on in the Security pane of Safari preferences.

Disable Runaway JavaScript Timer

The Runaway JavaScript Timer interrupts the execution of very slow scripts, so you can regain control of Safari. Disabling it is useful for some types of automated testing.

Disable Site-specific Hacks

Some versions of Safari contain special-case code that allows certain webpages to behave normally while Apple engineers work with you to find a better long-term solution. This option turns off that special-case code, so you can test your long-term solutions.

### Related Topics

Developing websites for Safari