function isValidEmail(txt)
{
	  var objRegExp  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;


      //check for valid email
     if(objRegExp.test(txt)){
           return true;
     }
    else{
      return false;
       }
}



function checkFieldsInForm(theForm) {
   
   var borderstyle_veld = "1px #7F9DB9 solid";
   var borderstyle_vergetenveld = "3px #FF0000 solid";
   
   var alertText = "Sorry, uw formulier kon niet worden verzonden omdat \neen aantal verplichte velden niet of niet goed zijn ingevuld:\n\n";
   doSubmitform = true;
   check_radio_fieldname = "";
   
   for(i=0; i<theForm.elements.length; i++){
       if(theForm.elements[i].name.match("_#v")){
      	  if(theForm.elements[i].type == "text" || theForm.elements[i].type == "textarea" || theForm.elements[i].type == "button"){
		       
		  	   if(theForm.elements[i].value.length < 1){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#v","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Vergeten veld: " + stripedFieldName + "\n";
					theForm.elements[i].style.border=borderstyle_vergetenveld;
					doSubmitform = false;
			   }
			   else {
					theForm.elements[i].style.border=borderstyle_veld;

			   }
      	  }
		  else if(theForm.elements[i].type == "checkbox"){
		  	   if(!theForm.elements[i].checked){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#v","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Vergeten vinkje: " + stripedFieldName + "\n"
					theForm.elements[i].style.border=borderstyle_vergetenveld;
					doSubmitform = false;
			   }
			   else {
					theForm.elements[i].style.border=borderstyle_veld;
			   }
      	  }
      	  else if(theForm.elements[i].type == "select-one"){
		  	   if(theForm.elements[i].options[theForm.elements[i].selectedIndex].value.length < 1){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#v","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Vergeten keuze: " + stripedFieldName + "\n"
					theForm.elements[i].style.background="#ff0000";
					doSubmitform = false;
			   }
			   else {
					theForm.elements[i].style.background="#ffffff";
			   }
      	  }
      	  else if(theForm.elements[i].type == "radio" && check_radio_fieldname != theForm.elements[i].name){
		  	   check_radio_fieldname = theForm.elements[i].name;
			   control_radio_checked = false;
		  	   for(j=0; j<theForm.elements.length; j++){
			   	   if(theForm.elements[j].name == check_radio_fieldname) {
				   	  if(theForm.elements[j].checked){
					   	  control_radio_checked = true;
					  }
				   }
			   }
			   if (!control_radio_checked){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#v","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Vergeten keuze: " + stripedFieldName + "\n"
					//theForm.elements[i].style.border=borderstyle_vergetenveld;
					doSubmitform = false;
		  	   		for(j=0; j<theForm.elements.length; j++){
			   	   	  if(theForm.elements[j].name == check_radio_fieldname) {
					    theForm.elements[j].style.border=borderstyle_vergetenveld;
					  }
			   		}
			   }
			   else {
					//theForm.elements[i].style.border=borderstyle_veld;
		  	   		for(j=0; j<theForm.elements.length; j++){
			   	   	  if(theForm.elements[j].name == check_radio_fieldname) {
					    theForm.elements[j].style.border=borderstyle_veld;
					  }
			   		}
			   }
      	  }
	  }
	  if(theForm.elements[i].name.match("_#e")){
		  	   if(theForm.elements[i].value.length < 1){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#e","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Vergeten veld: " + stripedFieldName + "\n"
					theForm.elements[i].style.border=borderstyle_vergetenveld;
					doSubmitform = false;
			   }
			   else if(!isValidEmail(theForm.elements[i].value)){
   			   		stripedFieldName = theForm.elements[i].name.replace("_#e","");
					stripedFieldName = stripedFieldName.replace(/_/g," "); 
      	  			alertText += "Ongeldige email: " + stripedFieldName + "\n"
					theForm.elements[i].style.border=borderstyle_vergetenveld;
					doSubmitform = false;
			   }
			   else {
					theForm.elements[i].style.border=borderstyle_veld;
			   }
	  }
   }
   if(doSubmitform) {
		return true;
   }
   else {
   		alert(alertText);
   		return false;
   }
}