Spellchecker

A spellchecker, so spelled,  is a program that automatically checks a user's spelling on a written text.

Although the state-of-the-art spellcheckers provide pretty reliable results when revising a text, students (and users in general), may need to be reminded that there is no way the application can detect mistakes such as "it's" for "its" or "here" for "hear". Students of English as a second language may have more problems, as exemplified by "tower" for "towel", or "bear" for "beer", etc.

In other words, they cannot yet tell the difference between syntactical/semantical mistakes and spelling mistakes, as in the following:

Available spellcheckers
The Firefox and Chrome browsers include a built-in spellchecker.