Is there another code for just SPACE?
Yes. Try  
instead of
<!DOCTYPE html>
<html>
<head>
<title>
</title>
<body>
<div>Just testing  space</div>
</body>
</html>
質問
I'm trying to validate my own code right now. I got the error
"no document type declaration; implying "< !DOCTYPE HTML SYSTEM>""
When i put < DOCTYPE> at the beginning of my code, i get errors for the " " i used in my code. i used " " to align my numbers.
Is there another code for just SPACE?
this is the outline of my code is:
<html>
<head>
<title>...... </title>
</head>
<body>............</body>
</html>
解決
Is there another code for just SPACE?
Yes. Try  
instead of
<!DOCTYPE html>
<html>
<head>
<title>
</title>
<body>
<div>Just testing  space</div>
</body>
</html>
他のヒント
ensure you have a ;
at the end of  
so it's
You can do something like this:
<!DOCTYPE html>
<html>
<head>
<title>
</title>
<body>
</body>
and you can learn more about DOCTYPE here