14 tips for Website Optimization

April 4, 2009

Some following tips are derived from the book High Performance Web Sites (O’Reilly) by Steve Souders:

  1. Make fewer HTTP requests to reduce object overhead.
  2. Use a content delivery network.
  3. Add an Expires header.
  4. Gzip/compress text components.
  5. Put stylesheets at the top in the head.
  6. Put scripts at the bottom of the body.
  7. Avoid CSS expressions which are CPU-intensive and can be evaluated frequently.
  8. Make JavaScript and CSS files external.
  9. Reduce Domain Name System (DNS) lookups to reduce the overhead of DNS delay by splitting lookups between two to four unique hostnames.
  10. Minify JavaScript.
  11. Avoid redirects which slow performance. It’s better to CNAME or alias.
  12. Remove duplicate scripts to eliminate extra HTTP requests in Internet Explorer.
  13. Configure ETags for sites hosted on multiple servers. FileETag none in Apache removes Etags to avoid improper cache validation.
  14. Make Ajax cacheable and small to avoid unnecessary HTTP requests.

Tips to Avoid Web Form SPAM

June 30, 2007

Web forms are now a routine target of spammers. Whether your web site is a personal one just looking for feedback or a commercial site generating sales leads, getting dozens of entries for link exchanges or online gambling sites isn’t anyone’s idea of useful feedback
It can be really disturbing when you started to getting lots of useless SPAM through the web form on your site. 

Is there something we can do about it?

Luckily, the answer is yes.

I found few interesting articles.

Method 1:

Checking for the value of HTTP_USER_AGENT, if it is empty that means it is not from any browser. 

Method 2:

Simple, but powerful. Having an extra text box but make it invisible using CSS, check if the textbox has any value in your server script. If the text box has a value in it, that means it is not a regular user’s input.

The demo page is here

Disable F1 Key in IE (Internet Explorer)

March 1, 2007

document.onhlep=new Function(“return false”);
window.onhelp=new Function(“return false”);