Javascript Reference - JavaScript atan() Method
The atan() method returns the arctangent
value between -PI/2 and PI/2 radians.
Browser Support
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|---|---|---|---|---|---|
atan() |
Yes | Yes | Yes | Yes | Yes |
Syntax
Math.atan(x);
Parameter Values
| Parameter | Description |
|---|---|
| x | Required. A number |
Return Value
It returns the arctangent value between -PI/2 and PI/2 radians.
It returns NaN if the value is empty.
Example
The following code shows how to calculates the arctangent of a number.
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function doMath() {<!--from ww w . ja v a 2s . c o m-->
var inputNum = document.form1.input.value;
var result = Math.atan(inputNum);
document.form1.answer.value = result;
}
</script>
</head>
<body>
<form name=form1>
This example calculates the arctangent of the input number. <br>
<br> Enter Number: <input type="text" name="input" size=10>
<input type="button" value="Calculate" onClick='doMath()'> <br>
The arctan is: <input type="text" name="answer" size=10>
</form>
</body>
</html>