Based on the application you are building the web standards check list should be considered. Web standards are understood differently by different individuals, but the primary motto is to make the application standardized so that any user around the world can understand and navigate through the website without any effort or confusion. To make this happen, there is a big list to check upon when you are building a web application, below are the points you might want to review before you go live:

Checklist for web standards.

The checklist

1.Quality of code

• Proper Doctype definition
• Usage of Character set
• Valid CSS.
• Usage of CSS hacks.

Few of the CSS hack techniques are:

• Box model hack
• Underscore hack
• Star hack
• Star HTML hack
• Star plus hack
• Child selector hack
• Negation pseudo-class hack
• body: empty hack
• !important quirks

•  Avoiding unnecessary classes or ids.
• Well structured code.
• Check and avoid any broken links.
• Perform in terms of speed/page size.
• Check for JavaScript errors

2.Content and presentation

1. Using CSS for presentation like fonts, color, borders, padding, etc
2. Images in the CSS, or do they appear in the (X)HTML.

3.Users Accessibility

1.  “alt” attributes should be used for all descriptive images.
2. The site should use relative units rather than absolute units for text size.
3. No aspects of the layout should break if font size is increased.
4. The site should use visible skip menus.
5. The site should use accessible forms.
6. The site should use accessible tables.
7. There should be sufficient color brightness/contrasts.
8. Critical information should be colored.
9. There should be no delayed responsiveness for drop-down menus.
10. All the links should be descriptive.

4.Devices Accessibility

1. The site should work for modern and older browsers.
2. The content should be accessible even if the CSS is turned off or not supported.
3. The content should be accessible even if the images are switched off or not supported.
4. The site should be accessible in text browsers like as Lynx.
5. The site should work well when print is given.
6. The site should work in portable or Hand Held devices.
7. The site should include detailed metadata.
8. The site should work in different browser window sizes.

5.Basic Usability

1. Clear visual hierarchy should be maintained.
2. Application of distinguished heading levels.
3. Easy and understandable site navigation.
4. Consistent site navigation.
5. Consistent and appropriate language should be maintained.
6. Having and easy to find sitemap page and contact page in the site.
7. Search tool for searching the site.
8. Every page should have a link to home page.
9. Links should be underlined.
10. Clear identification of visited links.

6.Site management

1. The site should have a meaningful and helpful 404 error page that works from any depth in the site.
2. The site should use friendly URLs.
3. The URLs should work without “www”.
4. The site should have a favicon.