There are some scholars who prohibit this behavior under all circumstances. Therefore, it is not permissible to spit in the direction of prayer much like it is not permissible to relieve oneself towards that direction. Some scholars maintained that the prohibition is only restricted to when someone is in prayer. This is because some narrations are narrated mentioning this restriction,
“When you are in prayer, do not spit in front of you!’ (Bukhaary, 416)
Some narrations restrict the action only to the mosque. In any case, avoiding filth and dirty things is desirable in legislation even though it might not be prohibited. The direction of the prayer should be safeguarded from such filthy acts. However, if it is done, no objections can be made against the person who does so because the narration refers to it specifically being in prayer or in a mosque, and Allaah knows best.