When searching on pathofexile.com/trade, this addon inserts the tilde(~) before your search query. This enables fuzzy search, so you can be more lenient with your search. Start you search with a space (" ") to not use fuzzy search for this query.
For example, when searching for "#% to Fire and Cold Resistance" it's enough to just write "fire cold res". Without fuzzy search, this would not find the modifier.
Without fuzzy search:
With fuzzy search:
This Extension is available for Firefox, Chrome or as a Greasemonkey userscript
Just install it from the Firefox Webstore here
Available from the Chrome Webstore here
The POETradeFuzzySearch.gm_script file contains a userscript for the Greasemonkey Extension (or any of its alternatives). This should work with any browser that has a Greasemonkey extension.