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Strings in JavaScript




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In this video we will discuss different functions that are available to manipulate string in JavaScript.

A string is any text inside quotes. You can use either single or double quotes.
var string1 = “string in double quotes”
var string2 = ‘string in single quotes’

Concatenating strings : There are 2 options to concatenate strings in JavaScript. You could either use + operator or concat() method

Example : Concatenating strings using + operator
var string1 = “Hello”
var string2 = “JavaScript”
var result = string1 + ” ” + string2;
alert(result);

Output : Hello JavaScript

Example : Concatenating strings using concat() method
var string1 = “Hello”
var string2 = “JavaScript”
var result = string1.concat(” “, string2);
alert(result);

Output : Hello JavaScript

If you want single quotes inside a string, there are 2 options
Option 1 : Place your entire string in double quotes, and use single quotes inside the string wherever you need them.

Example :
var myString = “Welcome to ‘JavaScript’ Training”;
alert(myString);

Output : Welcome to ‘JavaScript’ Training

Option 2 : If you prefer to place your entire string in single quotes, then use escape sequence character with a single quote inside the string.

Example :
var myString = ‘Welcome to ‘JavaScript’ Training’;
alert(myString);

Output : Welcome to ‘JavaScript’ Training

Please Note : You can use the above 2 ways if you need double quotes inside a string

Converting a string to uppercase : Use toUpperCase() method

Example :
var upperCaseString = “JavaScript”;
alert(upperCaseString.toUpperCase());

Output : JAVASCRIPT

Converting a string to lowercase : Use toLowerCase() method

Example :
var lowerCaseString = “JavaScript”;
alert(lowerCaseString.toLowerCase());

Output : javascript

Length of string javascript : Use length property

Example : alert(“JavaScript”.length);

Output : 10

Example :
var myString = “Hello JavaScript”;
alert(myString.length);

Output : 16

Remove whitespace from both ends of a string : Use trim() method

Example :
var string1 = ” AB “;
var string2 = ” CD “;
var result = string1.trim() + string2.trim();
alert(result);

Output : ABCD

Replacing strings in javascript : Use replace() method. This method searches a given string for a specified value or a regular expression, replaces the specified values with the replacement values and returns a new string. This method does not change the original string.

Example : Replaces JavaScript with World
var myString = “Hello JavaScript”;
var result = myString.replace(“JavaScript”, “World”);
alert(result);

Output : Hello World

Example : Perform a case-sensitive global replacement. In this example, we are using a regular expression between the 2 forward slashes(//). The letter g after the forward slash specifies a global replacement. The match here is case sensitive. This means Blue(with capital B) is not replaced with green.

var myString = “A Blue bottle with a blue liquid is on a blue table”;
var result = myString.replace(/blue/g, “green”);
alert(result);

Output : A Blue bottle with a green liquid is on a green table

Example : Perform a case-insensitive global replacement. The letters gi after the forward slash indicates to do global case-insensitive replacement. Notice that the word Blue(with capital B) is also replaced with green.

Nguồn: https://vinhtrinh.com.vn

Xem thêm bài viết khác: https://vinhtrinh.com.vn/cong-nghe/

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  • var a = "mahesh";

    var b = "naresh";

    for(var i=0;i<a.length;i++){

    for(var j=0;j<b.length;j++){

    if(a.charAt(i)==b.charAt(j)){

    a.replace(a.charAt(i),'');

    b.replace(b.charAt(j),'');

    i–;

    break;

    }

    }

    }

    document.write("<h2>"+a+" "+b+"</h2>");

    why this js program isn't working


  • Thank you for detailed and easy explanations


  • Very nice tutorial series! Much in depth knowledge about javascript programming! Thanks a lot!!!
    Will you please make a tutorial series on Java?


  • Thanks


  • thank u sir


  • /* Thanks */
    /* Replace ALL */

    a="12-02-2018";
    bb=a.replace(/-/g,'=');
    alert(bb);


  • Thank u so much Sir


  • how to deal with variable

    —————————————
    var myString = "A Blue bottle with a blue liquid is on a blue table";
    var name='blue';
    var result = myString.replace(/'name'/g, "green");
    alert(result);


  • Explain it String s = string2.trim(); ????????????


  • I watched your few videos you are great teacher


  • Thank you sir


  • excellent


  • pure awesome;


  • You do all explanations very good and with proper speed. Thanks man, you helped me a lot


  • You do all explanations very good and with proper speed. Thanks man, you helped me a lot


  • Nice way to explain


  • Thanks abillions.


  • excellent mehtod !!!
    I m very thankful of U Sir >>>


  • amazing very clear explanation..thank you sir 🙂


  • sdsd

    Author Reply

    YOU'RE THE BEST+EST ! Thanks!


  • clear easy explanation. to-the-point. full of practical examples & applications of javascript.. Thank u very much Venkat


  • This guy covers everything. FANSTASTIC!


  • Great tutorial thank you very much


  • Thanks for video +kudvenkat  


  • Great video!  You may want to note that string.trim() is not supported in older IE versions such as IE8.