Mobile Emulator is an useful online tool to check the screen resolution on different mobile and tablet devices.

Mobile Emulator is an useful online tool to check the screen resolution on different mobile and tablet devices.

Do your mobile screen resolution check for developed mobile website straight from your desktop.

Mobile devices supported:

 BlackBerry: 320x240

 iphone4s: 320x480

 iphone5: 320x568

 Galaxy S3: 360x640

 Lumia 900: 480x800

Tablet devices supported:

 Kindle Fire 7: 533x853

 Google Nexus: 603x966

 Apple iPad: 768x1024

Best way to check screen responsive design for mobile devices & tablet online

   

Test your web pages on common mobile and tablet devices/user agents. Excellent for testing responsive web design.

This extension allows web designers and developers to test their web pages against common mobile and tablet devices by emulating the user agent and screen resolution. Excellent for testing responsive web designs. Test multiple mobile devices at the same time!

Very helpful when your site is in development and testing on actual devices can be difficult.

** New in version 1.4**

 - Larger device label and scroll arrows

 - Galaxy Note II added

 - Scrollbar removed quicker

**New in version 1.3**

 - Width and heights adjusted to account for Chrome borders.

 - Scroll bar removed and scrolling arrows added to the bottom of the window

 - A couple more devices added

 - New logo

 - Various bug fixes

Speed Tracer：

Speed Tracer是一款功能强大的Web性能分析扩展，能够对网页中的元素进行全方位的检測分析，找出你网页执行缓慢的罪魁祸首。以方便开发人员优化代码，功能非常强大。

COMMON

• Add the features:
  • Auto Reload
  • Check Spelling
  • Clean Submit
  • Clear Application Cache
  • Disable CSS3 Styles
  • Disable Flash
  • Disable Frames
  • Disable HTML5 Form Validation
  • Disable Image Maps
  • Disable Redirects
  • Disable Sound
  • Disable Window Resize
  • Display Baseline Grid
  • Display Canonical URL
  • Display Event Information
  • Display Margin & Padding
  • Display Screen Size Overlay
  • Make Element Resizable
  • Outline Image Maps
  • Outline No Follow Links
  • Outline No Index Elements
  • Remove Inline Styles
  • Replace Images With Title Attributes
  • Validate Generated HTML
  • Validate Local Accessibility
  • Validate Tidied HTML
  • View Color Contrast Information
  • View Computed Style
  • View Font Information
  • View Formatting
• 'Display Element Information' should display color information
• 'Display Line Guides' should allow saving the line guide positions
• 'Display Line Guides' should be able to be pinned
• 'Display Style Information' should display inherited styles
• 'Edit CSS' should have a color picker
• 'Edit CSS' should notify when style sheets have invalid MIME types
• 'Populate Form Fields' should be configurable
• 'Validate Local CSS' and 'Validate Local HTML' validators should be configurable
• 'View Link Information' should display the link text, title and target
• 'View Link Information' should separate internal and external links
• Add a warning when closing the dashboard after changes have been made
• Add support for beautifying CSS
• Add support for element position in 'Display Element Information'
• Add support for gradients in 'View Color Information'
• Add support for importing and exporting of the extension options
• Add support for sorting 'View Color Information' by color instead of alphabetically
• Add support for wrapping text output
• Allow templates of activated features to be saved and loaded
• Allow the Web Developer menus to be customized
• Allow unlimited customizable bookmarklets as tools
• Use %s and %d placeholders for the site URL and domain in a tool URL

CHROME

• Add the features:
  • Display Page Magnifier
  • Display Style Information
  • View Generated Source
• Add JavaScript status icon
• Add quirks mode status icon
• Add support for customizable keyboard shortcuts

FIREFOX

• Add the features:
  • Enable Retina Mode
• 'View Generated Source' should be able to be opened in
  a tab
• 'View Source With' should be allowed to be the default
  for all view source features
• Add support for automatically closing the message notifications
  after a few seconds
• Add support for disabling the cache only for certain
  domains
• Allow features to be pinned per tab
• Context menu features should work only on the selected
  frame
• Detect keyboard shortcut conflicts

Speed Tracer：

Speed Tracer是一款功能强大的Web性能分析扩展，能够对网页中的元素进行全方位的检測分析。找出你网页执行缓慢的罪魁祸首，以方便开发人员优化代码，功能非常强大。

Speed Tracer：

Speed Tracer是一款功能强大的Web性能分析扩展，能够对网页中的元素进行全方位的检測分析，找出你网页执行缓慢的罪魁祸首。以方便开发人员优化代码，功能非常强大。