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Question: Should I paste the JavaScript Vision files into my HTML Web pages, use CFINCLUDE to place them in my CFM files, or use the SRC attribute of the SCRIPT tag?

Answer: The SRC attribute of the SCRIPT tag is available in Internet Explorer 4+ and Netscape 3+ browsers. If you use the SRC attribute to load JavaScripts into your Web pages and your users are not using Internet Explorer 4+ and Netscape 3+ browsers, then they will get an error when the JavaScript is executed. Knowing which browsers your pages will be viewed in will help you decide the best means of using JavaScript files. (See the JavaScript Vision Custom ColdFusion Tag for a means to load JavaScript Vision files into ColdFusion Web pages.)

See the webreference DHTML Diner article Loading External JS Files for DHTML Browsers.

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Question: How can I use the JavaScript Vision Custom ColdFusion Tag custom tag to automatically detect whether the browser being used can use the SRC attribute of the SCRIPT tag?

Answer: By using the CGI.USER_AGENT variable to establish the browser and version, one can then establish whether to include or link to the JavaScript Vision files. (Two free tags, CF_Browser and CF_BrowserCheck, both translate the browser's USER_AGENT value into a set of variables that can be used in your ColdFusion Web pages. You can also develop your own or purchase a commercial version.) For example:

<CF_Browser>
<CFSET jsvUsage = "INCLUDE">
<CFIF ( BrowserType is "MSIE" and Version GTE "4" ) OR
        (BrowserType is "NS" and Version GTE "3")>
    <CFSET jsvUsage = "LINK">
</CFIF>
<CFSET jsvPath =
    IIf(  jsvUsage IS "INCLUDE",
          DE("../jsvInclude/"),
          DE("http://www.roaringforksoftware.com/JSV/")
          )>
<CFMODULE TEMPLATE="JS_VISION.cfm"
          MODULE="windowmgmt"
          USE="#jsvUsage#"
          MODULEPATH="#jsvPath#">

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Question: Is there any other way I can access the JavaScript Vision library, or any other JavaScript code, other than pasting it into each document or using the SRC attribute of the SCRIPT tag?

Answer: Yes, but this option is not for the faint of heart. Use a hidden frame that contains a Web page with all the JavaScript that you want to reference (e.g., the JavaScript Vision library) pasted in it. To access a function from the hidden Web page on each visible Web page, you must provide a reference to that function (e.g., parent.frames[0].JSV_isEmpty()).

See:

• JavaScript Frame FAQ Knowledge Base
• Q524  Where can I get more information regarding "hidden frames" is there any site where I can get more information?
• Frames Tutor

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Question: How do I work around the limitations of the JavaScript getYear method?

Answer: The best answer would be to use the getFullYear method but this method is available only in JavaScript 1.3. However, note what it says below for the different versions of JavaScript and JScript. One could use a browser sniffer and determine whether to call the the getFullYear method or the the getYear method, but this may not be reliable with browsers other than Netscape and Internet Explorer. That is why JSV_getFullYear function is recommended over the getFullYear or getYear method.

Browser	JavaScript Version
Navigator 2 and IE3	1.0
Navigator 3 and Opera	1.1
Navigator 4.05 and lower and IE4	1.2
Navigator 4.06 and higher and IE5	1.3
Navigator 5	1.4

JavaScript 1.3. The getYear method returns the year minus 1900; thus:

• For years above 2000, the value returned by getYear is 100 or greater. For example, if the year is 2026, getYear returns 126.
• For years between and including 1900 and 1999, the value returned by getYear is between 0 and 99. For example, if the year is 1976, getYear returns 76.
• For years less than 1900 or greater than 1999, the value returned by getYear is less than 0. For example, if the year is 1800, getYear returns -100.

• For years between and including 1900 and 1999, the value returned by getYear is the year minus 1900. For example, if the year is 1976, the value returned is 76.
• For years less than 1900 or greater than 1999, the value returned by getYear is the four-digit year. For example, if the year is 1856, the value returned is 1856. If the year is 2026, the value returned is 2026.

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Question: How do I center a browser window on the screen?

Answer: Carefully. This is due to the differences between Netscape Navigator and Internet Explorer in which size property of window they support.

For either Internet Explorer or Netscape, I recommend the following procedure to center a window using JavaScript Vision:

1. Create a default set of x,y delta values (see JSV_xyValues) for each window opened. Why? Due to the differences in the call to each window. (Was the window opened with status? menubar? scrollbars? location?) This is currently only needed for Internet Explorer as the outerWidth and outerHeight window properties are not supported.
   
   For example
   var windowDeltas1 = new JSV_xyValues();
    
2. Create a set of x,y values (see JSV_xyValues) for each window opened with the width and height attributes passed to window.open(). These will be the initial values to compute the deltas.
   
   For example
   var windowOuterDim1 = new JSV_xyValues(500,300);
    
3. Calculate the actual deltas for the Internet Explorer window using the JSV_getWindowDeltas function.
   
   For example
   windowDeltas1 = JSV_getWindowDeltas(windowOuterDim1, myWindowHandle);
    
4. Get the current dimensions of the browser window using JSV_getWindowDimensions. For Netscape, the window deltas will be zero and the JSV_getWindowDimensions function will return the outerWidth and outerHeight values. For Internet Explorer, the window deltas may not be zero and the JSV_getWindowDimensions function will return the innerWidth and innerHeight values with the window deltas added.
   
   For example
   var windDimensions1 = JSV_getWindowDimensions(windowHandle1, windowDeltas1);
    
5. The last step is to get the position values for the left and top of the window using JSV_windowCenter, then pass these values to the moveTo method of window.
   
   For example
   var centerTopLeft = JSV_windowCenter(windDimensions1);
windowHandle1.moveTo(centerTopLeft.x, centerTopLeft.y);

If you are dealing strictly with Netscape Navigator and a resizable window, then you need only pass the outerWidth and outerHeight values of the window to the JSV_windowCenter function. If you are dealing with Internet Explorer, then you need to follow the above steps.

If the browser window is not resizable, then you need only pass the values of the width and height attributes, when the browser window was open, to the JSV_windowCenter function.

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Question: Does it cost anything to use the JavaScript Vision library?

Answer: All code provided on this site is free for use, provided that any copyright notices remain intact and that those web pages are freely accessible, i.e., not on pay sites. Use on an intranet is permitted. You may not sell or distribute the code without permission. All rights are retained by the author.

You are not required to display any links or buttons if you use code from this site. However, if you do wish to add a link please make it to the home page of this site (http://www.roaringforksoftware.com/).

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Question: May I alter your code for my own purposes?

Answer: Yes you may, however any copyright is retained by the author as provided by law and any such notices must still be included in the code.

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