计算增加和减少的百分比

Question

anyone can write a PHP script as this calculator that calculates the percentage of increase and decrease?

http://www.marshu.com/articles/calculate-percentage-increase-decrease-percent-calculator.php

Thank you.

Answer 1

If you open the source of that page, you will find following:

function PercentIncrease(form) {
   var num1 = form.num1.value;
   var num2 = form.num2.value;
   return ((num2 - num1) / num1 * 100 + "%");
}

Let us know if you have problems with PHP syntax.

Update: Obviously you have, so:

function PercentIncrease($num1, $num2) {
    return (($num2 - $num1) / $num1 * 100 . "%");
}

$n1 = 10;
$n2 = 200;
echo PercentIncrease($n1, $n2); //output 1900%
echo PercentIncrease($n2, $n1); //output -95%

Answer 2

You could make a function like :

function calcPercentInc($a, $b)
{
    return (100 * (($a / $b) - 1)) . '%';
}