Solved

javascript simple question

Posted on 2013-01-29
2
248 Views
Last Modified: 2013-01-29
why when I put javascript code into <head> section , it is not working, only when I
put it into body section:

<head>


 /* read jquery etc */

</head>
<body>


<select>
 <option> 1 </option>
 <option> 2 </option>
  
</select>
 
 <script>

	
 $("select").change(function() {

 	 

 	var sel	=	$(this).val();

 	if  (sel != 0 )
 	{
 	 		
	}		

	});  			


</script> 

</body>
</html>

Open in new window

0
Comment
Question by:sniger
2 Comments
 
LVL 82

Accepted Solution

by:
leakim971 earned 500 total points
ID: 38833849
When you put it in the body, AFTER the select box, it mean the select is already in the document (because you put it after)
When you put it in the head section, the body is not loaded, no select so you can play with it

You need to be sure document object model is ready to use
http://james.padolsey.com/javascript/some-jquery-shortcuts/
http://www.learningjquery.com/2006/09/introducing-document-ready
http://web.enavu.com/daily-tip/daily-tip-difference-between-document-ready-and-window-load-in-jquery/

<head>


 /* read jquery etc */
 <script>
$(document).ready(function() { // wait the DOM is ready to use
	
 $("select").change(function() {

 	 

 	var sel	=	$(this).val();

 	if  (sel != 0 )
 	{
 	 		
	}		

	});  			

})
</script> 
</head>
<body>
<select>
 <option> 1 </option>
 <option> 2 </option>  
</select>
</body>
</html>

Open in new window

0
 
LVL 21

Expert Comment

by:Tapan Pattanaik
ID: 38833851
Hi  sniger,

JavaScript writes into the HTML <body> while the page loads.

Please check this link.

http://www.w3schools.com/js/js_howto.asp
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

What is a Lightbox? A Lightbox is the effect you see when you click, for example, an image and the screen fades out and up pops the same image but in its full size dimensions. There are lots of Lightbox effects for jQuery. Problem is they are a…
I found this questions asking how to do this in many different forums, so I will describe here how to implement a solution using PHP and AJAX. The logical flow for the problem should be: Write an event handler for the first drop down box to get …
The viewer will learn the basics of jQuery, including how to invoke it on a web page. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery.: (CODE)
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…

929 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now