the best way for opening javascript?

(1) <script type="text/javascript">

(2) <SCRIPT LANGUAGE="JavaScript">

(3) <script>


Which is the best practice for opening javascript?

if possible, could you tell my the reason in short?

The first one is the best way for the script tag, reason being, the 2nd one has language="javascript" which is deprecated and shouldn't be used any more, and the 3rd one, you are missing the type attribute, which is needed if you want it o validate.

Option 1 is the only one you should use.

JavaScript is the default scripting language, so if you used



<script>
// code here
</script>



Your browser would know its JavaScript but the standard nowadays is the incode type="text/javascript"

(1) <script type="text/javascript">

(2) <script language="javascript">


Which is more recommendable between (1) and (2) in the above quote?

as stated above, use 1 since language is deprecated.

(1) <script type="text/javascript">
(2) <script type='text/javascript'>


Which is more recommendable between double quotation mark and single quotation mark?

<script type="text/javascript">
...
</script>

OR

<script src="/myapp/afile.js" type="text/javascript"></script>

Which is more recommendable between double quotation mark and single quotation mark?
Just like in any other HTML attributes, use double quotes.