Topic awaiting preservation: variables and namespaces ?

Hello,


I'm having bad times guessing problems like when using external script between my actual js code...example:

<script>
dx = 1234;
</script>
<script src='file1.js'></script>
<script>
alert(dx);
</script>

now 'dx' will print other than 1234, why?! cause that 'file1.js' modified it...

most scripts we use use common variable namings like layername, layerwidth, i, x, y, dx, dy, etc etc....

can't I specify a name space when I include that external script and then specify another name space when using my own scripts? just to avoid such variables overwritings....

Not really
I haven't played to much with it but I usually consider all variables global.

You can define function specific variables by using the var statement with in the function. However any variables declared within the "global" space will be availible to all.



:[ Computers let you make more mistakes faster than any other invention in human history, with the possible exceptions of handguns and tequila. ]:

You can give your variables a sort of namespace like this. it is a bit long winded to set up the vars but you should be able to protect them from the external script.
Anyay, see what you think.

<SCRIPT>

myVars = new Object();

//You always have to create variables with "myVars."

myVars.dx = 10;

myVars.dy = 10;

//create functions that don't conflict

myVars.hello = function(str)

{

	alert("hello "+str);

}

</SCRIPT>

<SCRIPT SRC="test.js"></SCRIPT>

<!--- suppose it contains the following code --->

<SCRIPT>

dx = 1000;

dy = 1000;

function hello(str)

{

	alert("Ola " + str);

}

</SCRIPT>



<SCRIPT>

//Use "with" as a shortcut to access your variables

with(myVars)

{

	alert(dx);

	alert(dy);

	hello("world");



	dz = 10; // !!! Does not create myVars.dz !!!



	dx += 5;  //Does change the value of myVars.dx

	alert(dx); //Output 15

}

//Now outside myVars namespace



alert(myVars.dz); //Output "undefined"

alert(dz);		//Output 10 (not defined in myVars namespace)

hello("world");

</SCRIPT>

I originally got this tip from somewhere in Doc Javascript http://www.webreference.com/js/

I'm not really sure because I don't use Namespaces in Javascript, however it looks like namespaces are supported in Javascript 2.0 from this link:
http://www.mozilla.org/js/language/js20/core/namespaces.html

I hope that helps.



[This message has been edited by Bugimus (edited 10-11-2001).]