About Javascript Inbuilt functions
JavaScript offers you to access a number of built-in features, including the prompt() function, which helps you to ask the consumer for written input. As with the confirm() function, you present a text prompt to ask the user to provide a value. On return, you set the output of the function equal to the prompt() function and use the data in your software.
- The functions are a reusable code-block that will be executed at any time when it’s called.
- It’s used for performing repetitive tasks where you can call the same function a number of times to get the same impact.
- The functions also use to validate user forms and alerts.
List of Javascript built-in functions
- parseFloat (string): If the string begins with a number, the function reads by way of the string till it finds the end of the number; cuts off the remainder of the string, and returns the end result. If the string doesn’t start with a number, the function returns NaN.
- length(): Returns the number of characters in the string and also returns the number of elements in the array.
- toString(): Outputs the value of the object as a string. This method is commonly used for display purposes.
- isNan(): Returns true, if the object isn’t a number or an illegal number and it returns False when the object is number.
- decodeURI(): Decodes a Uniform Resource Identifier Replaces every escape sequence within the encoded URI with the character that it represents, however, doesn’t decode escape sequences that might not have been launched by
encodeURI
. The character “#
” will not be decoded from escape sequences.
- decodeURIComponent(): Replaces every escape sequence within the encoded URI component with the character that it represents. Its Decodes only a URI component, rather than the whole URI.
- encodeURI(): The function doesn’t encode characters that have particular meaning for a URI.
- Number(): The Number() function converts the object argument to a number and used to represent and manipulate numbers like 24If the value can’t be transformed to a legal number, NaN is returned.
- parseInt(): The ParsesInt() parses a string and returns an integer value.
- eval(): Returns the results of evaluating an arithmetic expression.
Accepts a string that contains a script after which executes the string content as a script. Many developers use this function to create self-modifying functions that present good flexibility.
Evaluated code runs extra slowly as a result of the browser can’t compile after which cache it.
Example: Create a User define function
User-defined function means you may create a function on your personal use. You’ll be able to create your self based on your want.
Syntax:
function functionName()
{
//Write Javascript Code Here;
}
Sample Code of javascript functions basic syntax: Javascript Function Declaration
function multiplyTwoNum()
{
N1 = document.getElementById(“textbox1”).value;
N2 = document.getElementById(“textbox2”).value;
document.getElementById(“showResult”).innerHTML = N1 * N2;
}
function divideTwoNum()
{
N1 = document.getElementById(“textbox1”).value;
N2 = document.getElementById(“textbox2”).value;
document.getElementById(“showResult”).innerHTML = N1 / N2;
}
function addTwoNum()
{
N1 = document.getElementById(“textbox1”).value;
N2 = document.getElementById(“textbox2”).value;
document.getElementById(“showResult”).innerHTML = N1 + N2;
}
function subTwoNum()
{
N1 = document.getElementById(“textbox1”).value;
N2 = document.getElementById(“textbox2”).value;
document.getElementById(“showResult”).innerHTML = N1 – N2;
}
Sample HTML Code and javascript inbuilt functions
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>JavaScript program to calculate Addition, multiplication and division of two numbers | javascript inbuilt functions </title>
</head>
<body>
<form>
Input Number 1 : <input type=”text” id=”textbox1″ /><br>
Input Number 1 : <input type=”text” id=”textbox2″ /><br>
<input type=”button” onClick=”multiplyTwoNum()” Value=”Multiplication” />
<input type=”button” onClick=”divideTwoNum()” Value=”Divide” />
<input type=”button” onClick=”addTwoNum()” Value=”Addition” />
<input type=”button” onClick=”subTwoNum()” Value=”Addition” />
</form>
<p>The Result print here : <br>
<div id = “showResult”></div>
</p>
</body>
</html>