Js window close prompt information (compatible with IE and firefox) _ javascript tips-js tutorial

This article mainly introduces window prompts and friendly prompts when the window is closed to prevent loss of important information. For more information, see the following, we need to consider the situation where users close the window when they are not careful, especially when the user has important data that has not been saved, it is necessary for our program to remind the user. In this case, we can use javascript window. onbeforeunload () to prevent users from closing the window. See the following example: