SharePoint: Search Results are not being returned when we use special characters.
We could face a problem in searching the special characters by using the GET method.
For example, I have a document which has the German characters in it. I have indexed the document already. In the URL type the following, and hit enter.
Now check the site context search box. It has the word “verffentlichten” missing the “ö” character. This results the invalid search result.
If I replace the default search box with my custom one as per the following msdn article that also results the same result
Creating a Site Context Search Box that Uses SharePoint Portal Server Search Results
Solution: In the custom search box code, use the “escapeProperly” function which is defined in the ows.js file. This will encode the URL appropriately and will return the expected result.