Replace special characters in a string with _ (underscore)

Question

I want to remove special characters from a string and replace them with the _ character.

For example:

string = "img_realtime_tr~ading3$" 

The resulting string should look like "img_realtime_tr_ading3_";

I need to replace those characters: & / \ # , + ( ) $ ~ % .. ' " : * ? < > { }

Answer 1

string = string.replace(/[&\/\\#,+()$~%.'":*?<>{}]/g,'_'); 

Alternatively, to change all characters except numbers and letters, try:

string = string.replace(/[^a-zA-Z0-9]/g,'_'); 

Answer 2

string = string.replace(/[\W_]/g, "_");