function check(){
		var x = document.getElementById('email').value;
		var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
		if(!document.getElementById('name').value){
			alert("Please fill in your name.");
		}else if(!document.getElementById('email').value){
			alert("Please fill in your email.");
		}else if (!filter.test(x)) {
			alert('email is wrong.');
		}else if(!document.getElementById('comment').value){
			alert('Please enter your comment.');
		}else if(!document.getElementById('scode').value){
			alert('Please enter security code.');
		}else {
			return true;
		}
		return false;
	}
	
	show_hide_comment=function(id,type){
		if(type==1){
			if(id==1){
				document.getElementById('navi').innerHTML='<a href="javascript:;" onclick="show_hide_comment(\'0\',\'1\');">Hide Comments</a>';
				document.getElementById('comments').style.display='';
			}else{
				document.getElementById('navi').innerHTML='<a href="javascript:;" onclick="show_hide_comment(\'1\',\'1\');">Show Comments</a>';
				document.getElementById('comments').style.display='none';
			}	
		}else{
			if(id==1){
				document.getElementById('navi').innerHTML='<a href="javascript:;" onclick="show_hide_comment(\'0\',\'0\');">Hide  Comments</a>';
				document.getElementById('comments').style.display='';
			}else{
				document.getElementById('navi').innerHTML='<a href="javascript:;" onclick="show_hide_comment(\'1\',\'0\');">Leave a comment</a>';
				document.getElementById('comments').style.display='none';
			}	
		}
	}