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-   -   Javascript: Multiple Code Blocks (http://www.daniweb.com/forums/thread102426.html)

DavidB Dec 25th, 2007 6:18 pm
Javascript: Multiple Code Blocks
 
Hi, folks.

I have written some pretty complicated programs in Javascript (in terms of the code itself), but I haven’t experimented much with the nuts-and-bolts of Javascript. In particular, I have written all my programs as single blocks of code. For example, I have written several programs to solve for the eigenvalues and eigenvectors of matrices. One page solves for a 3 x 3 matrix, one for a 4 x 4 matrix, one for a 5 x 5 matrix, etc. Each javascript program is on its own page and takes the following form:

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

<!--Define JavaScript function.-->



function OneBigProgram(dataForm){



// Code to input the matrix elements for the specifically-sized matrix



 . . .



// Code to calculate the eigenvalues and eigenvectors

// BIG BLOCK OF CODE

. . .



// Code to output the results for the specifically-sized matrix

 . . . 



// end of JavaScript-->

</script>

The algorithm for actually calculating the eigenvalues and eigenvectors does not change depending upon matrix size, it is included in the BIG BLOCK OF CODE.

What I am hoping to do now is turn the code block for the BIG BLOCK OF CODE into an external file, and have the several programs refer to it. That way, I won't have six programs include the same big block of code; they can all refer to the same external file--saving space on the server. For example:

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

<!--Define JavaScript function.-->



function A_Smaller_Program_Input(dataForm){



// Code to input the matrix elements for the specifically-sized matrix



 . . .



// end of JavaScript-->

</script>

<script language="javascript" type="text/javascript" src="RoutineforEigenvalues.js">

</script>

function A_Smaller_Program_Output(dataForm){



// Code to output the results for the specifically-sized matrix



 . . .



// end of JavaScript-->

</script>

Is what I want to do possible? How seamlessly does Javascript transmit data between seemingly independent code blocks?

hielo Dec 26th, 2007 1:47 am
Re: Javascript: Multiple Code Blocks
 
You have the right syntax. Just save your program as eigenValues3.js and then if you want to write a program that needs that file you just "import" it as follows:
<html>

<head>

<script type="text/javascript" src="eigenValue3.js"></script>

<script type="text/javascript">

//The code that will use the functions in eigenValue3.js goes here

</script>

</head>

<body>...

</body>

</html>

Note: 1. You do not have to do the "import" within the <head> tag. It could have done withing the <body> tag.
2. <script> tags that are used to import files cannot enclose javascript code (or at least this was the case last time I tested this about 1yr ago). That's why I have two <script> tags above. The first one to import the file. The second to write my code for my local/current page.
3. You do not need language="javascript". Providing type="text/javascript" will suffice.


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