check if string contains numbers, letters jquery check if string contains specific character In this article weâ ll cover various methods that work with regexps in-depth. In the above program, the indexOf () method is used with the if...else statement to check if a string contains a substring. The backslash symbol (\\) is used as an escape character for a single quote, double quote, backslash, tab, etc. Check If String Contains Substring In JQuery - C# Corner To find a character in a String has to use a includes() method in the JavaScript program. To check whether string contains particular text or not in jQuery we need to write the code like as shown below.