Page 308 - Web Applications (803) Class 11
P. 308
The various methods to explicitly convert data are as follows:
Method Description Example
Number( ) Converts any value to number. NaN is returned if the value cannot be Number(false)
converted. Output:0
Number(“77”)
Output:77
Number(“69 58”)
Output:NaN
parseInt( ) This method accepts two arguments and returns an integer value. parseInt(“30 years”)
Syntax: parseInt(string, radix) Output: 30
string—The value that has to be parsed (required) parseInt(“20.43”)
radix—The default value is 10. The number system is specified by Output: 20
numbers 2–36. (Optional) parseInt(“He is 30 years”)
Output: NaN
parseInt(“20”, 8)
Output: 16
parseFloat( ) The parseFloat() method returns the first decimal number after parsing parseFloat(“20.45”)
a value as a string. NaN is returned if the initial character cannot be Output: 20.45
converted. parseFloat(“44 56”)
Output:44
eval( ) A JavaScript expression is passed as a string argument to this method. eval(“5*4”)
After that, eval( ) evaluates the expression and returns the result. It Output: 20
returns undefined if no result is received.
String A value is converted to a string. String(false)
Output: false
String(Boolean(1))
Output: true String(“65”)
Output: 65
Boolean Checks if an expression is true. Boolean(20 > 7)
Output: true
X=null; Boolean(X)
Output: false
Example:
<!DOCTYPE html>
<HTML>
<BODY>
<H1>JavaScript Global Methods</H1>
<H2>The eval() Method</H2>
<SCRIPT>
l x = 10;
let y = 20;
let text = "x * y";
let result = eval(text);
306 Touchpad Web Applications-XI

