JavaScript Tutorial/Number Data Type/Float
Содержание
Adding the float point numbers together
<html>
<head>
<title>GoodAdd</title>
</head>
<body>
<script>
var meal;
meal = 123.45;
meal = eval(meal);
var tip = meal * .15;
var total = meal + tip;
alert ("the meal is $" + meal);
alert ("the tip is $" + tip);
alert ("Total bill: $" + total);
</script>
</body>
</html>
Floating-Point Numbers
Floating-point numbers can contain fractional parts.
Floating-point numbers can use exponential notation for added precision.
Floating-point numbers are made up of a decimal integer followed by a period (.) and the fractional portion of the number.
Exponential notation can be used by adding an e or E to the end of a floating-point number followed by a decimal integer that does not exceed 3 digits.
Use 1.0 not 1.
var fNum = 1.0;
Floating-point values can be represented using e-notation
In e-notation, a number is represented by digits, followed by an e or an E, followed by the number of times to multiply it by 10.
var fNum = 3.125e7;
This notation represents the number 31250000.
You can get this value by converting the e-notation to a calculation: 3.125 * 10^7.
0.00000000000000003 can be written as 3e-17.
Here, 10 is raised to the -17 power.
By default, JavaScript converts any floating-point number with six or more leading zeros into e-notation.
Floating-point values are stored in a 64-bit IEEE 754 format.
Decimal values can have up to 17 decimal places.
After that, the values are truncated.
float point value
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<BODY>
<SCRIPT language="JavaScript">
<!--
var myVariable=2.59;
document.write(myVariable);
//-->
</SCRIPT>
</BODY>
</HTML>