JAVASCRIPT

js check if string contains character

"FooBar".includes("oo"); // true

"FooBar".includes("foo"); // false

"FooBar".includes("oo", 2); // false

javascript string contains character

var email = "grepper@gmail.com";
if(email.includes("@")){
  console.log("Email is valid");
}
else{
  console.log("Email is not valid");
}
// includes return boolean, if your string found => true else => false

js contain character

bigstring.includes("string") // return true or false

js check if string contains character

if (your_string.indexOf('hello') > -1)
{
  alert("hello found inside your_string");
}