function stripBad(string) {
    //for (var i=0, output='', valid="eE+/*-0123456789.()"; i<string.length; i++)
	for (var i=0, output='', valid="0123456789"; i<string.length; i++)
       if (valid.indexOf(string.charAt(i)) != -1)
          output += string.charAt(i)
    return output;
}

function yieldchecker(elem1,elem2) {

	document.getElementById("ycerr").innerHTML="&nbsp;";
	document.getElementById("myyield").value="";
	var elem1=document.getElementById(elem1);
	var elem2=document.getElementById(elem2);
	var a=0;
	var b=0;
	if ((elem1.value!="") && (elem2.value!="")){
		if(!isNaN(stripBad(elem1.value))){
			a = stripBad(elem1.value) * 12;
		}
		if(!isNaN(stripBad(elem2.value))){
			b = a / stripBad(elem2.value);
		}
		if(a!=0 && b!=0){
			c = b * 100;
			document.getElementById("myyield").value=c+"%";
		}
		else{
			//document.getElementById("ycerr").display="";
			document.getElementById("ycerr").innerHTML="* Only numeric values must be entered!";
		}
	}
	else{
		//this is not valid values, display error...
		//document.getElementById("ycerr").style.display="";
		document.getElementById("ycerr").innerHTML="* Only numeric values must be entered!";
	}
	return false;
}