Performance Tip 4 -
Use innerHTML to Add Many Options to a SELECT Element

When you add a large number of OPTION elements to a SELECT element, it is more efficient to use the innerHTML property than to call the createElement method to access the options collection.

For very large numbers of options, build an array and call the Microsoft® JScript join method to perform a final concatenation of the OPTION element HTML text.

Click the buttons to see the difference in performance.