Javascript Reference - JavaScript log() Method
The log() method returns the natural logarithm (base E) of a number.
Browser Support
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log() |
Yes | Yes | Yes | Yes | Yes |
Syntax
Math.log(x);
Parameter Values
| Parameter | Description |
|---|---|
| x | Required. A number |
Return Value
A number representing the natural logarithm of a specified number.
If the parameter x is negative, NaN is returned.
If the parameter x is 0, -Infinity is returned.
Example
The following code shows how to calculate the natural logarithm (base E) of a number.
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function doMath() {<!-- ww w. ja v a 2 s .co m-->
var inputNum = document.form1.input.value;
var result = Math.log(inputNum);
document.form1.answer.value = result;
}
</script>
</head>
<body>
<form name=form1>
This example calculates the natural log of the number entered. <br>
<br> Enter First Number: <input type="text" name="input" size=15>
<input type="button" value="Calculate" onClick='doMath()'> <br>
The log is: <input type="text" name="answer" size=10>
</form>
</body>
</html>