Só Calculadoras: Calculadora Ciêntifica Simples

Calculadora Ciêntifica Simples

<script type="text/javascript">
//<!--

// The Javascript bit:

var sign = "";
var total = 0;
function calcClear()
 {
  sign = "";
  total = 0;
  calc.output.value = "";
 }
function calcOutput(num)
 {
  outnums = calc.output;
  outnums.value = outnums.value + num;
 }
function calcOp(oper)
 {
  sign = oper;
  total = calc.output.value;
  calc.output.value = "";
 }
function equals()
 {
  curr = eval(calc.output.value);
  prev = eval(total);
  if (curr == null || prev == null)
   {
    ans = "Need two numbers."; // If an operation was selected without two numbers
                               // I.E. "5+" or "/3"
   }
  else
   {
    if (sign == "add")
     {
      ans = prev + curr;
     }
    else if (sign == "subtract")
     {
      ans = prev - curr;
     }
    else if (sign == "multiply")
     {
      ans = prev * curr;
     }
    else if (sign == "divide")
     {
      if (curr == 0)
       {
        ans = "Can't divide by zero"; // If "x/0" is entered.
       }
      else
       {
        ans = prev / curr;
       }
     }
    else if (sign == "")
     {
      ans = calc.output.value; // If no sign is selected, display same value.
     }
   }
  calc.output.value = ans;
 }

// Now for the HTML bit (corresponding form id's)
// Sorry, this is mainly tables to make it look nice-ish.
//-->
</script>

<form action="" method="post" id="calc">
 <table style="border:1px solid #ccc;">
  <tr>
   <td colspan="4">
    <input type="text" disabled="disabled" name="output" value="" />
   </td>
  </tr>
  <tr>
   <td>
    <input type="button" name="bttn" value="  7  " onclick="calcOutput(7)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  8  " onclick="calcOutput(8)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  9  " onclick="calcOutput(9)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  +  " onclick="calcOp('add')" />
   </td>
  </tr>
  <tr>
   <td>
    <input type="button" name="bttn" value="  4  " onclick="calcOutput(4)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  5  " onclick="calcOutput(5)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  6  " onclick="calcOutput(6)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  −  " onclick="calcOp('subtract')" />
   </td>
  </tr>
  <tr>
   <td>
    <input type="button" name="bttn" value="  1  " onclick="calcOutput(1)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  2  " onclick="calcOutput(2)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  3  " onclick="calcOutput(3)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  ×  " onclick="calcOp('multiply')" />
   </td>
  </tr>
  <tr>
   <td>
    <input type="reset" name="bttn" value="  c  " onclick="calcClear()" />
   </td>
   <td>
    <input type="button" name="bttn" value="  0  " onclick="calcOutput(0)" />
   </td>
   <td>
    <input type="button" name="bttn" value="  •  " onclick="calcOutput('.')" />
   </td>
   <td>
    <input type="button" name="bttn" value="  ÷  " onclick="calcOp('divide')" />
   </td>
  </tr>
  <tr>
   <td colspan="4">
    <input type="button" name="bttn" value="              =               " onclick="equals()" />
   </td>
  </tr>
 </table>
</form>