<!-- http://speedpigeon.com -->
function Calculator_OnClick(keyStr)
{
	var resultsField = document.calculator.calcResults;

	switch (keyStr)
	{
		case "0":
		case "1":
		case "2":
		case "3":
		case "4":
		case "5":
		case "6":
		case "7":
		case "8":
		case "9":
		case "0":
		case ".":
		
			if ((this.lastOp==this.opClear) || (this.lastOp==this.opOperator))
			{					
				resultsField.value = keyStr;
			}
			else
			{
				// ignore extra decimals
				if ((keyStr!=".") || (resultsField.value.indexOf(".")<0))
				{
					resultsField.value += keyStr;
				}
				
			}

			this.lastOp = this.opNumber;
			break;
		
		case "*":
		case "/":
		case "+":
		case "-":
			if (this.lastOp==this.opNumber)
				this.Calc();
			this.evalStr += resultsField.value + keyStr;
		
			this.lastOp = this.opOperator;
			break;
		
		case "=":
			this.Calc();
			this.lastOp = this.opClear;
			break;
		
		case "c":
			resultsField.value = "0";
			this.lastOp = this.opClear;
			break;
			
		default:
			alert("'" + keyStr + "' not recognized.");
	}

}

function Calculator_Calc()
{
	var resultsField = document.calculator.calcResults;
	//alert("eval:"+this.evalStr+resultsField.value);
	resultsField.value = eval(this.evalStr+resultsField.value);
	this.evalStr = "";
}

function Calculator()
{
	this.evalStr = "";

	this.opNumber = 0;
	this.opOperator = 1;
	this.opClear = 2;
	
	this.lastOp = this.opClear;
	
	this.OnClick = Calculator_OnClick;
	this.Calc = Calculator_Calc;
}

racing_pigeon = new Calculator();