Functions are the block of code that performs specific task and often return a value. Any function can be understood as a reusable code-block that will be executed by an event, or when the function is called. A javaScript function may return zero or more parameters. Parameters can be understood as the standard technique of passing control to a function. JavaScript functions can be of two types:
1. Built-In Function: JavaScript provides a set of in built function that can be used to perform specific functions Some of them are eval(),parseInt(),parseFloat().
a. eval(): eval() function is used to convert a string expression a numeric value
E.g. Evaluating a expression using eval()
var a=eval(“5*5+6”);
eval() function evaluates the expression and assigns 26 to variable a .
Note: In case you pass a string value as a parameter eval() expression will not be generated. You need to convert the data type. This can be done using parseInt() discussed below:
b. parseInt(): parseInt() function is used to convert a string value to an integer. It returns the first integer contained in the string. The function will return a 0 value in case string does not begin with an integer.
E.g. var a=parseInt(“89hello”);
In above example parseInt will return the first two integer value i.e a=89
E.g:
var h=(“89hello”);
var a=parseInt(h);
In above example parseInt will return the first two integer value of string stored in variable h.
c. parseFloat(): Just like a parseInt() function parseFloat() is used to convert a string value to float value.
E.g. Applying all the three built in functions
Output:
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