1var string = "my name";
2string = string.replace(/ /g,"_"); //returns my_name
1// replaces spaces with '_'
2str = str.replace(/ /g, "_");
3// or
4str = str.split(' ').join('_');
1const name = 'Hi my name is Flavio'
2name.replace(/\s/g, '') //HimynameisFlavio
3
1var string = "Javascript is fun";
2var newString = string.replace(" ", "_");
3console.log(newString); // Javascript_is_fun