js if has especific text code example

Example 1: js check if string contains character

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

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

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

Example 2: js check if string contains character

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