function getCheckedValue(radioObj) {
        if(!radioObj)
               return "";
        var radioLength = radioObj.length;
        if(radioLength == undefined)
               if(radioObj.checked)
                       return radioObj.value;
               else
                       return "";
        for(var i = 0; i < radioLength; i++) {
               if(radioObj[i].checked) {
                       return radioObj[i].value;
               }
        }
        return "";
}
function imageChange()
{
        return true;
}
function calculateBMI()
{
        var weight = document.getElementById('bmi_gewicht').value;
        var length = document.getElementById('bmi_lengte').value;
        var gender = getCheckedValue(document.forms['bmi'].elements['bmi_gender']);
        var bmi = "0";
        if (length > 149 && weight > 30) {
               var bmiLength = (length/100) * (length/100);
               bmi = Math.round(weight/bmiLength, 1);
        }
        writeResult(gender, length, weight, (Math.round((getIdealWeight(length, gender)*10),1)/10), bmi);
}
function writeResult (g, l, w, ideal, b, r)
{
   if (g=='') {alert('U dient uw geslacht op te geven.'); return;}
   g = (g=='male')? 'man':'vrouw';
   if (l > 149 && w > 47) {
var difT='gewichtsverschil'; var difW=Math.round((w-ideal)*10)/10; var res='Uw gewicht is bijna ideaal. Blijf vooral in beweging om dit mimimaal zo te houden.';
     if ((w-ideal)>2.49) {
       difT = 'overgewicht';
       difW = Math.round((w-ideal)*10)/10;
       res = 'Een paar kledingmaatjes kleiner bereikt u al snel door op uw voeding te letten en te trainen.';
     }
     if ((ideal-w)>1.49) {
       difT = 'ondergewicht';
       difW = Math.round((ideal-w)*10)/10;
       res = 'Door kort maar krachtig te trainen, kunt u spiermassa opbouwen en gewicht toenemen.'
     }


     var content = "Uw BMI is: " + b + "\nUw ideale gewicht is: " + ideal + "kg\nUw " + difT + " is: " + difW + "kg\n" + res;
   } else {
     var content = 'De waardes die u heeft ingevult voldoen niet aan onze voorwaarden. Voor het berekenen van een goede BMI is een minimaal gewicht vereist van 47,1 kg en een minimale lengte van 150cm.'
   }
   alert(content);
}

function getIdealWeight(length, gender)
{
        if (gender == 'male') {
               var idealWeight = getMaleWeight(length);
        } else {
               var idealWeight = getFemaleWeight(length);
        }
        if (idealWeight > 0) {
               return idealWeight
        }
        return "";
}

var maleBaseWeight = 47.8;
var maleBaseLength = 150;
var maleBaseAddition = 0.9;
function getMaleWeight(length)
{
        if (length<maleBaseLength) return "";
        var maleDifference = length - maleBaseLength;
        var maleIdealWeight = maleBaseWeight + (maleDifference * maleBaseAddition);
        return maleIdealWeight;
}

 var female = new Array();
 female[150] = 47.4;
 female[151] = 48.1;
 female[152] = 48.7;
 female[153] = 49.4;
 female[154] = 50.1;
 female[155] = 50.8;
 female[156] = 51.5;
 female[157] = 52.2;
 female[158] = 52.7;
 female[159] = 53.4;
 female[160] = 54.1;
 female[161] = 54.8;
 female[162] = 55.4;
 female[163] = 56.1;
 female[164] = 56.8;
 female[165] = 57.4;
 female[166] = 58.1;
 female[167] = 58.8;
 female[168] = 59.4;
 female[169] = 60.1;
 female[170] = 60.8;
 female[171] = 61.4;
 female[172] = 62.1;
 female[173] = 62.8;
 female[174] = 63.5;
 female[175] = 64.1;
 female[176] = 64.8;
 female[177] = 65.5;
 female[178] = 66.1;
 female[179] = 66.8;
 female[180] = 67.5;
 female[181] = 68.1;
 female[182] = 68.8;
 female[183] = 69.5;
 female[184] = 70.1;
 female[185] = 70.8;
 female[186] = 71.5;
 female[187] = 72.2;
 female[188] = 72.8;
 female[189] = 73.5;
 female[190] = 74.2;
 female[191] = 74.8;
 female[192] = 75.5;
 female[193] = 76.2;
 female[194] = 76.8;
 female[195] = 77.5;
 female[196] = 78.2;
 female[197] = 78.9;
 female[198] = 79.5;
 female[199] = 80.2;
 female[200] = 80.9;
 female[201] = 81.5;
 female[202] = 82.2;
 female[203] = 82.9;
 female[204] = 83.5;
 female[205] = 84.2;
 female[206] = 84.9;
 female[207] = 85.5;
 female[208] = 86.2;
 female[209] = 86.9;
 female[210] = 87.6;

function getFemaleWeight(length)
{
        returnLength = female[length];

        if (length>210 || length<150) {
            alert('De door u opgegeven lengte komt niet voor in ons systeem');
            return '';
        } else {
            return returnLength;
        }
}