javascript: how do i push a radio value to another function?

can't get the variable taxRate to be seen in the function called by the following form. blargh! :P

here's the HTML:

<form name="incomeRange" id="incomeRange" title="Taxable Income Ranges">
  <legend>Income Range:</legend>            
    <p name="incomeTable" id="incomeTable">
      please make a selexion: <br>
      <label>
        <input type="radio" name="B" id="B_1" value="200" onChange="var taxRate = (this.value);">200
  </label>
</p>
</form>
<form name="userAmount" id="userAmount">
  <p>Target Amount to Spend:
    <input type="text" name="userTargetAmount" id="userTargetAmount" onKeyUp="doTheMath(this.value);">
  </p>
</form>

and the function it calls:

function doTheMath(amount)
{
  var targAmt = document.getElementById("targetAmount");
  var taxAmt = document.getElementById("taxAmount");
  var totTaxEarn = document.getElementById("totalTaxedEarnings");
  var taxRt = document.getElementById("taxRate");

  console.log(amount);
  console.log(taxRate);

  if (!isNaN(amount))
  {
    targAmt.innerHTML = amount;
    totTaxEarn.innerHTML = amount / taxRate;
    taxRt.innerHTML = ta开发者_C百科xRate;
    taxAmt.innerHTML = (amount / taxRate) - amount;
  }
}

guess where it explodes? taxRate is not visible from within this function. i thought that by setting it with the onChange of the radio button, this would make it accessible... but i guess not. how can i get that value into the variable such that i can be used in the doTheMath(); function?

thanks for your time. srsly. :)

WR!

PS: and this time, i'm unlikely to figure it out on my own... i've spent three hours on this one... :P

---

The problem is in following code:

    <input type="radio" name="B" id="B_1" value="200" onChange="var taxRate = (this.value);">200

taxRate is declared with 'var' keyword makes it is visible on 'onChange' event only. Please remove 'var' keyword.

---

Skip the 'onchange' handler, and just get the currently selected value in doTheMath. I would do it with jQuery this way:

$('radio[name=B]:checked').val()