大小写金额转换

<script>
 function regInput(reg)
 {
  var srcElem = event.srcElement
  var oSel = document.selection.createRange()
  oSel = oSel.duplicate()
  oSel.text = ""
  var srcRange = srcElem.createTextRange()
  oSel.setEndPoint("StartToStart", srcRange)
  var num = oSel.text + String.fromCharCode(event.keyCode) + srcRange.text.substr(oSel.text.length)
  event.returnValue = reg.test(num)
 }

 function chineseNumber(num)
 {
  if (isNaN(num) || num > Math.pow(10, 12)) return ""
  var cn = "零壹贰叁肆伍陆柒捌玖"
  var unit = new Array("拾佰仟", "分角")
  var unit1= new Array("万亿", "")
  var numArray = num.toString().split(".")
  var start = new Array(numArray[0].length-1, 2)
  
  function toChinese(num, index)
  {
   var num = num.replace(//d/g, function ($1)
   {
    return cn.charAt($1)+unit[index].charAt(start--%4 ? start%4 : -1)
   })
   return num
  }
  
  for (var i=0; i<numArray.length; i++)
  {
   var tmp = ""
   for (var j=0; j*4<numArray[i].length; j++)
   {
    var strIndex = numArray[i].length-(j+1)*4
    var str = numArray[i].substring(strIndex, strIndex+4)
    var start = i ? 2 : str.length-1
    var tmp1 = toChinese(str, i)
    tmp1 = tmp1.replace(/(零.)+/g, "零").replace(/零+$/, "")
    tmp1 = tmp1.replace(/^壹拾/, "拾")
    tmp = (tmp1+unit1[i].charAt(j-1)) + tmp
   }
   numArray[i] = tmp 
  }
  
  numArray[1] = numArray[1] ? numArray[1] : ""
  numArray[0] = numArray[0] ? numArray[0]+"圆" : numArray[0], numArray[1] = numArray[1].replace(/^零+/, "")
  numArray[1] = numArray[1].match(/分/) ? numArray[1] : numArray[1]+"整"
  return numArray[0]+numArray[1]
 }

 function aNumber(num)
 {
  var numArray = new Array()
  var unit = "亿万圆$"
  for (var i=0; i<unit.length; i++)
  {
   var re = eval("/"+ (numArray[i-1] ? unit.charAt(i-1) : "") +"(.*)"+unit.charAt(i)+"/")
   if (num.match(re))
   {
    numArray[i] = num.match(re)[1].replace(/^拾/, "壹拾")
    numArray[i] = numArray[i].replace(/[零壹贰叁肆伍陆柒捌玖]/g, function ($1)
    {
     return "零壹贰叁肆伍陆柒捌玖".indexOf($1)
    })
    numArray[i] = numArray[i].replace(/[分角拾佰仟]/g, function ($1)
    {
     return "*"+Math.pow(10, "分角 拾佰仟 ".indexOf($1)-2)+"+"
    }).replace(/^/*|/+$/g, "").replace(/整/, "0")
    numArray[i] = "(" + numArray[i] + ")*"+Math.ceil(Math.pow(10, (2-i)*4))
   }
    else numArray[i] = 0
  }
  return eval(numArray.join("+"))
 }
</script>

<input id=up size=60 onkeypress="regInput(/^/d{0,12}(/./d{0,2})?$/)"><button onclick="lw.value = chineseNumber(up.value)">转为大写</button><br>
<input id=lw size=60 value="壹仟壹佰壹拾壹圆整"><button onclick="up.value = aNumber(lw.value)">转为小写</button>