<?php  /* PHP不使用速算扣除數計算個人所得稅   * @author 吳先成   * @param float $salary 含稅收入金額   * @param float $deduction 保險等應當扣除的金額 默認值為0   * @param float $threshold 起征金額 默認值為3500   * @return float | false 返回值為應繳稅金額 參數錯誤時返回false  */  function getPersonalIncomeTax($salary, $deduction=0, $threshold=3500){    if(!is_numeric($salary) || !is_numeric($deduction) || !is_numeric($threshold)){      return false;    }    if($salary <= $threshold){      return 0;    }    $levels = array(1500, 4500, 9000, 35000, 55000, 80000, PHP_INT_MAX);    $rates = array(0.03, 0.1, 0.2, 0.25, 0.3, 0.35, 0.45);    $taxableIncome = $salary - $threshold - $deduction;    $tax = 0;    foreach($levels as $k => $level){      $previousLevel = isSet($levels[$k-1]) ? $levels[$k-1] : 0;      if($taxableIncome <= $level){        $tax += ($taxableIncome - $previousLevel) * $rates[$k];        break;      }      $tax += ($level-$previousLevel) * $rates[$k];    }    $tax = round($tax, 2);    return $tax;  }  /* 示例 */  echo getPersonalIncomeTax(10086.11);  //運行結果：762.22?>