function extract_only_characters(s) {
var len = s.length;
var chars = "";
for (var i = 0; i < len; i++) {
ch = s[i];
var regex = /^[a-zA-Z]+$/;
if (ch.match(regex )) {
chars = chars + ch;
}
}
return chars;
}
var s = "c++14@vb.net&%JavaScript*() php <>/python 3.7.3";
document.write(extract_only_characters(s));
/*
run:
cvbnetJavaScriptphppython
*/