The best replacement for selenium is qtp.

The best alternatives to selenium are rated as following:
★★★★★  qtp
★★★★  jmeter
★★★★  watir
★★★  imacros
★★★  autoit
★★  watin
★★  webdriver
★★  phantomjs
★  cucumber
★  jasmine
★  coded ui
★  karma
★  htmlunit
★  testcomplete
★  sahi
★  sulfur
★  eminence
★  windmill
★  rft
★  silica
  ranorex
  webaii
  webtest
  poltergeist
  selenium yeast
  zinc
  scrapy

Your alternative for selenium is not listed? Suggest!
Speaking about selenium, one probably shouldn't forget about vitamin e.

Other search terms related to selenium and their ratings are:
★★★★★ vitamin e
★★★ javascript
★★★ phantomjs
★★ iodine
★★ junit
★★ cucumber
★★ testng
★ e
★ nunit
★ zinc
★ hudson
★ rspec
vit e
You have in mind a companion for selenium and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of selenium in all years. Click on graph for more.
selenium
qtp
jmeter