var bBtn = 0;

function CheckSingleInput(strInput) {


    var objstrInput = new String(strInput);
    objstrInput = objstrInput.replace(/,/g, ".");
    objstrInput = objstrInput.replace(/[\s\*-]/g, "");

    var nErg = objstrInput.search(/^[0-9]*[.]?[0-9]+$/);
    if (objstrInput.search(/^[0-9]*[.]?[0-9]+$/) == -1)
        return false;

    var fInput = parseFloat(objstrInput);
    if (!fInput)
        return false;
  
			
    return true;
}

function CheckInputData() {

    if (bBtn == 5)
        return true;

    var bResult = true;

    var rgbColor = '#FFFFCC';
    var rgbColorWhite = '#FFFFFF';
    var objGK = document.forms[0].inp_grundkapital;
    var objEK = document.forms[0].inp_endkapital;
    var objZS = document.forms[0].inp_zins;
    var objPD = document.forms[0].inp_period;
    
    objGK.style.backgroundColor = rgbColorWhite;
    objEK.style.backgroundColor = rgbColorWhite;
    objZS.style.backgroundColor = rgbColorWhite;
    objPD.style.backgroundColor = rgbColorWhite;

    if (!CheckSingleInput(objPD.value) && bBtn != 4) {
        objPD.style.backgroundColor = rgbColor;
        objPD.focus();
        objPD.select();
        bResult = false;
    }
    else {
        if (bBtn == 4)
            objPD.value = "";
    }

    if (!CheckSingleInput(objZS.value) && bBtn != 3) {
        objZS.style.backgroundColor = rgbColor;
        objZS.focus();
        objZS.select();
        bResult = false;
    }
    else {
        if (bBtn == 3)
            objZS.value = "";
    }

    if (!CheckSingleInput(objEK.value) && bBtn != 2) {
        objEK.style.backgroundColor = rgbColor;
        objEK.focus();
        objEK.select();
        bResult = false;
    }
    else {
        if (bBtn == 2)
            objEK.value = "";
    }

    if (!CheckSingleInput(objGK.value) && bBtn != 1) {
        objGK.style.backgroundColor = rgbColor;
        objGK.focus();
        objGK.select();
        bResult = false;
    }
    else {
        if (bBtn == 1)
            objGK.value = "";
    }

    return bResult;
}