includes()Returns if a string contains a specified value indexOf()Returns the index (position) of the first occurrence of a value in a string lastIndexOf()Returns the index (position) of the last occurrence of a value in a string
Now that thenewStringvariable contains our string, we can reference it and print it to the console. console.log(newString); Copy This will output the string value. Output This is a string assigned to a variable. By using variables to stand in for strings, we do not have to retype a s...
String.includes()The includes() method returns true if a string contains a specified value, otherwise false:Example let text = "Hello world, welcome to the universe."; text.includes("world") // Returns true Try it Yourself » String.startsWith()...
The value of the number usually depends on whether the result is true or false or whether the resultant string contains a number. To understand this better, consider the following examples: alert(true+true)//2 alert(true+false)//1 alert(false+false)//0 Each code sample is a Boolean ...
if(inputtxt.value.match(letters)) { return true; } else { alert("message"); return false; } } To get a string contains only letters (both uppercase or lowercase) we use a regular expression (/^[A-Za-z]+$/) which allows only letters. Next the match() method of string object is...
// Function to check letters and numbers function alphanumeric(inputtxt) { var letterNumber = /^[0-9a-zA-Z]+$/; if((inputtxt.value.match(letterNumber)) { return true; } else { alert("message"); return false; } } To get a string contains only letters and numbers (i.e. a-z,...
Let's dive into the article to learn more about inserting a space after every two letters in strings. For this,use replace()along with regular expressions. The replace() methodinJavaScript Thereplace()method returns a new string with one, some, or all matches of a pattern replaced by a ...
The purpose of a regular expression is to define a pattern of characters that you can then use to compare against an existing string. If the string contains characters that match the pattern, the regular expression tells you what the text is that matches the pattern and where the match occurs...
For example, if you want to validate an e-mail address, you must make sure it contains the characters “@” and “.” (note that this is not enough for 100% validation of an e-mail address, but it will work for now). To check whether a string contains another string, use the ...
Anexpressionproducesa value and can be written wherever a value is expected—for example, as an argument in a function call or at the right side of an assignment. Each of the following lines contains an expression: myvar3+xmyfunc('a','b') ...