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Miles Per Gallon Calculator

A function to calculate gas mileage.

Submitted By: OliveOyl3471

Actions:

Rating:

Views: 1,159

Language: JavaScript

Last Modified: October 13, 2008

Instructions: Copy and paste the function into the document head. Copy and paste the form into the document body.

Snippet

function calcMPG()
{
var startMiles = document.forms[0].startingMileage.value;
var endMiles = document.forms[0].endingMileage.value;
var gallons = document.forms[0].gallonsUsed.value;
if(isNaN(startMiles) || isNaN(endMiles) || isNaN(gallons))
{
window.alert("Each textbox must contain only numbers!");
}
else
{
if(gallons > 0)
{
document.forms[0].milesPerGallon.value = ((endMiles - startMiles)/gallons).toFixed(1);
}
}
}
<body>
<script type="text/javascript">
document.write("<p><h2>Miles Per Gallon Calculator</h2></p>");
document.write("<p><h5>To find miles per gallon, enter starting and ending mileage and gallons of gas used.</h5></p>");
</script>
<form action ="">
<p>Starting Miles:<br />
<input type = "text" name = "startingMileage" value = "0" size = "10" onchange = "calcMPG()" /></p>
<p>Ending Miles:<br />
<input type = "text" name = "endingMileage" value = "0" size = "10" onchange = "calcMPG()" /></p>
<p>Gallons Used:<br />
<input type = "text" name = "gallonsUsed" value = "0" size = "10" onchange = "calcMPG()" /></p>
<p>Miles Per Gallon:<br />
<input type = "text" name = "milesPerGallon" value = "0" size = "10" /></p>
</form>
</body>

Copy & Paste

<body>
<script type="text/javascript">
document.write("<p><h2>Miles Per Gallon Calculator</h2></p>");
document.write("<p><h5>To find miles per gallon, enter starting and ending mileage and gallons of gas used.</h5></p>");
</script>
	<form action ="">
		<p>Starting Miles:<br />
		<input type = "text" name = "startingMileage" value = "0" size = "10" onchange = "calcMPG()" /></p>
		<p>Ending Miles:<br />
		<input type = "text" name = "endingMileage" value = "0" size = "10" onchange = "calcMPG()" /></p>
		<p>Gallons Used:<br />
		<input type = "text" name = "gallonsUsed" value = "0" size = "10" onchange = "calcMPG()" /></p>
		<p>Miles Per Gallon:<br />
		<input type = "text" name = "milesPerGallon" value = "0" size = "10" /></p>
	</form>	
</body>

Comments
BetaWar 2008-10-13 16:34:40
Note for use: You need to fill in the top 3 fields for the calculation to be done. Interesting snippet :)
OliveOyl3471 2008-10-13 16:46:41
Thank you!
jjsaw5 2008-10-13 20:34:42
very nice Olive!