List with useful JavaScript methods for String, and functions to work with strings in JS scripts.
str.concat(s1, s2, ..) - joins the string 'str' with the substrings 's1, s2, ..' and returns a new string..
let str ='Hello, ';
let str2 = str.concat('CoursesWeb', '.net');
document.write(str2);
str.includes(s2) - returns True if the substring s2 is in 'str', otherwise returns False.
let str ='Life is Happiness, Be Happy.';
if(str.includes('Happ')) document.write('The string contains: Happ');
str.endsWith(s2) - returns True if the string 'str' ends with substring 's2', otherwise False. It is case-sensitive.
let str ='JavaScript string.';
if(str.endsWith('ing.')) document.write('The string ends with: ing.');
str.indexOf(s2) - returns the position of the first occurrence of the substring 's2' in 'str', or -1, if the substring is not found.
let str ='JS example string.';
var ix = str.indexOf('example');
if(ix !=-1) document.write('The word "example" starts from index: '+ ix);
str.match(RegExp) - Compares a regular expression and a string to see if they match. Returns an array with the matches or 'null'.
const email ='some_name@domain.net';
//is_em is an array like: ['email', 'name', 'domain'] or null
var is_em = email.match(/^([A-z0-9]+[A-z0-9._%-]*)@([A-z0-9_\-\.]+\.[A-z]{2,5})$/i);
//if email is a valid address writes the name
if(is_em){
document.write('The name from the address: "'+email+'" is: '+ is_em[1]);
}
str.repeat(nr) - returns a string consisting of the copies of the string 'str' repeated the given 'nr' times.let str ='abc'; let str2 = str.repeat(2); document.write(str2); // abcabc
str.replace(s0, s2) - replaces in 'str' the matched substring 's0' with the value from 's2'.
let str ='Visit: https://marplo.net';
let str2 = str.replace('marplo.net', 'gamv.eu');
document.write(str2); // Visit: https://gamv.eu
str.search(RegExp) - executes the search for a match between a regular expression and a specified string. Returns the position of the match, or -1 if no match is found.let str ='The Peace is peaceful'; var ix = str.search(/peace/i); document.write(ix); // 4
str.slice(start, end) - pulls out a specified section of a string (between start index and the end index) and returns a new string, or -1.let str ='Tutorials JS'; document.write(str.slice(0, 5)); //Tutor
str.split(separator, limit) - separates a string into an array of strings based on a separator sent as a parameter to the method. Limit is optional (an integer that specifies the number of splits).
let str ='How are you?';
var ar_str = str.split(' '); //['How', 'are', 'you?']
document.write(ar_str[1]); // are
str.startsWith(s2) - returns True if 'str' starts with 's2', otherwise False. Is case-sensitive.
let str ='Simple JavaScript string.';
if(str.startsWith('Simp')) document.write('The string starts with: Sim');
str.substr(start, length) - returns a portion of the string specified with a starting position and through the specified number of character (length).var str ='JS Tutorials'; document.write(str.substr(3, 5)); // Tutor
str.substring(start, end) - extracts the characters from a string, between two specified indices (not including "end" itself), and returns the sub-string.let str ='Hi everyone'; document.write(str.substring(3, 7)); // ever
str.toLowerCase() - returns the string to lowercase letters.let str = 'I love Peace'; document.write(str.toLowerCase()); // i love peace
str.toUpperCase() - returns the string to all uppercase letters.let str ='I love Peace'; document.write(str.toUpperCase()); //I LOVE PEACE
str.trim() - trims whitespace from the beginning and end of the string.
let str =' Hello to Me. ';
document.write('<pre>'+ str +' (without trim)</pre>');
document.write('<pre>'+ str.trim() +' (with trim)</pre>');
Aditional to this method are: trimStart() and trimEnd(). To trim whitespace from beginning or from the end.
str.toFixed(n) - formatting a number as a numeric string to a value rounded to 'n' decimals.let nr =78.468; document.write(nr.toFixed(2)); // 78.47
- You can find a list with the methods of the String object at MDN: String JavaScript.
escape(string) - converts most special characters to hexadecimal character codes (except: '@ * _ + - . /').let str ='Be&Well @!'; document.write(escape(str)); // Be&Well @!
unescape(string) - performs the reverse operation of the escape() function.let str ='Be&Well @! '; document.write(unescape(str)); // Be&Well @!
encodeURIComponent(string) - encodes characters that separate different components of a URL (except letters, digits, and the following characters: - _ . ! ~ * ` ( ) ).let str ='https://coursesweb.net/?x=abc'; document.write(encodeURIComponent(str)); // https://coursesweb.net/?x=abc
decodeURIComponent(string) - performs the reverse operation of the encodeURIComponent() function.let str ='https://coursesweb.net/?x=abc'; document.write(decodeURIComponent(str)); // https://coursesweb.net/?x=abc
<p>Address: <strong>http://CoursesWeb.net/</strong> - Tutorials.</p>
#id {
font-weight: 800;
}function someFunction() { alert("CoursesWeb.net"); }
setInterval("someFunction()", 2000);$vname = 8; echo $vname;