function checkoppervlak() {

	choice = document.getElementById('oppervlak').selectedIndex;

	var error = "";
    if (choice < 0) {
    
		if(o = document.getElementById('form_error_report'))
		{	
			o.innerHTML = '<span class="red">U dient een oppervlakte te selecteren.</span><br /><br />\n';
		}
		
		return false;
    }    
}    

function check_this_form()
{
	args = check;//check_this_form.arguments;
	
	phoneargs = phone;
	
	var ret = new Array();
	
	for (i=0; i<(args.length); i++)
	{	
		if((o = document.getElementById(args[i])) && args[i] != 'to')
		{
			if(o.value == '')
			{
				// fout
				o.style.backgroundColor = "#DDDDDD";
				ret[ret.length] = false;
			}
			else
			{
				// goed
				o.style.backgroundColor = "#FFFFFF";
			}
		}
	}
	
	var stripped = o.value.replace(/[\(\)\.\-\ ]/g, '');


	for (i=0; i<(phoneargs.length); i++)
	{	
		

		if((o = document.getElementById(phoneargs[i])) && args[i] != 'to')
		{
			if(o.value == '')
			{
				// fout
				o.style.backgroundColor = "#d8ecff";
				ret[ret.length] = false;
			}
			else if(isNaN(parseInt(stripped)))
			{
				// fout
				o.style.backgroundColor = "#ff8589";
				ret[ret.length] = false;
			}
			else
			{
				// goed
				o.style.backgroundColor = "#FFFFFF";
			}
		
		}
	}
		
	if(ret.length > 0)
	{
		if(o = document.getElementById('form_error_report'))
		{	
			o.innerHTML = 'De gemarkeerde velden zijn verplicht om in te vullen.';
		}
		
		return false;
	}
	else
	{
		return true;
	}
}