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  1. #1
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    Building a Table in JavaScript

    I am trying to create a table in JavaScript that contains a list of degrees, radians, sin, cos, and tan.

    I have the math right, but I am having trouble with the creating the table.

    It is not displaying. I know it is something simple, but I am missing it.

    Ideas?

    Code:
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
    <html><head><title>Computer Science 553 Lab Pages: Lab 3: Trig Functions On The Fly</title>
    <link rel="stylesheet" type="text/css" href="style.css" />
    </head>
    <body>
    <h1>Table of Sines, Cosines, and Tangents</h1>
    <h2>Charles P. Scott    |    9092</h2>
    <hr>
    
    <script type="taxt/javaScript">
    // Setting Up Variables
    var myTable			=	document.createElement("table");
    var tRowH			=	document.createElement('tr');
    var tCellH_Radians	=	document.createElement('th');
    var tCellH_Degrees	=	document.createElement('th');
    var tCellH_SinX		=	document.createElement('th');
    var tCellH_CosX		=	document.createElement('th');
    var tCellH_TanX		=	document.createElement('th');
    var angleR			=	0;
    var angleD			=	0;
    
    // Building the Table
    document.appendChild(myTable); // <table>
    
    // Creating the Header Row 
    myTable.appendChild(tRowH); // <th>
    
    // Building the Cells in the Header Row
    tRowH.appendChild(tCellH_Radians);
    tRowH.appendChild(tCellH_Degrees);
    tRowH.appendChild(tCellH_SinX);
    tRowH.appendChild(tCellH_CosX);
    tRowH.appendChild(tCellH_TanX);
    
    // Populate the Cells in the Header Row
    tCellH_Radians.appendChild(document.createTextNode('Radians'));
    tCellH_Degrees.appendChild(document.createTextNode('Degrees'));
    tCellH_SinX.appendChild(document.createTextNode('sin(x)'));
    tCellH_CosX.appendChild(document.createTextNode('cos(x)'));
    tCellH_TanX.appendChild(document.createTextNode('tan(x)'));
    
    for ( var i = 0; i < 25; i++ ) { // Loop to Build the Interior Table Cells
    
    // Setting Up Variables
    	var tRowC			=	document.createElement('tr');
    	var tCell_Radians	=	document.createElement('td');
    	var tCell_Degrees	=	document.createElement('td');
    	var angleRImg		=	document.createElement('img');
    		angleRImg.setAttribute('src', 'images/img' + angleD + '.gif');
    	var tCell_SinX		=	document.createElement('td');
    	var result_SinX		=	Math.round(Math.sin(angleR)*100000)/100000;
    	var tCell_CosX		=	document.createElement('td');
    	var result_CosX		=	Math.round(Math.cos(angleR)*100000)/100000;
    	var tCell_TanX		=	document.createElement('td');
    
    	// Building the Loop Row
    	myTable.appendChild(tRowC); // <tr>
    	if ((i+1)%2==0){
    		tRowC.setAttribute('class','alt'); // Sets up the Alternate Row Color
    	}
    	
    // Building the Table Cells
    	tRowC.appendChild(tCell_Radians);
    	tRowC.appendChild(tCell_Degrees);
    	tRowC.appendChild(tCell_SinX);
    	tRowC.appendChild(tCell_CosX);
    	tRowC.appendChild(tCell_TanX);
    
    // Populating the Cells
    	tCell_Radians.appendChild(angleRImg);
    	tCell_Degrees.appendChild(document.createTextNode(angleD + ""));
    	tCell_SinX.appendChild(document.createTextNode(result_SinX));
    	tCell_CosX.appendChild(document.createTextNode(resultCosX));
    		if ((angleD === 90) || (angleD === 270)){ // Setting Angles 90 and 270 to "Undefined"
    			var resultTanX = "Undefined";
    		}
    		else {
    			var resultTanX = Math.round(Math.tan(angleR)*100000)/100000;
    		}
    	tCell_TanX.appendChild(document.createTextNode(resultTanX));
    
    // Incrementing the Angles
    	angleR += Math.PI/12; // The Same as 15 Degrees
    	angleD += 15;
    }
    </script>
    
    <br /><br />
    <a href="javascript:history.go(-1)">[ Go Back ]</a>
    </body></html>

  2. #2
    SitePoint Evangelist silver trophybronze trophy
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    Hi JustAsIAm,
    Indeed some simple things/typo's:
    • A missing charset in the <head>: <meta http-equiv="content-type" content="text/html;charset=utf-8">

    • <script type="taxt/javaScript"> must be:
      <script type="text/javascript">

    • document.appendChild(myTable); must be:
      document.body.appendChild(myTable);

    • tCell_CosX.appendChild(document.createTextNode(resultCosX)); must be:
      tCell_CosX.appendChild(document.createTextNode(result_CosX));

    Then I get a table from 0 to 360 degrees in steps of 15.

  3. #3
    Programming Since 1978 silver trophybronze trophy felgall's Avatar
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    have you considered using table DOM commands insertCell(), insertRow() etc instead of manually creating each tag with createElement? The only two tags in a table that have to be created using a createElement call are 'table' and 'tbody', the rest can be done via table DOM calls.
    Stephen J Chapman

    javascriptexample.net, Book Reviews, follow me on Twitter
    HTML Help, CSS Help, JavaScript Help, PHP/mySQL Help, blog
    <input name="html5" type="text" required pattern="^$">

  4. #4
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    Francky, thank you for all of that. I ran some tests of my own and found the same things. (except for the <meta http-equiv="content-type" content="text/html;charset=utf-8"> thing). Why do I need that?

    felgall, I am very new to JS and although I finally got past document.write, this was my next level. I do not currently know anything about DOM calls. Want to enlighten me?

  5. #5
    Programming Since 1978 silver trophybronze trophy felgall's Avatar
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    Quote Originally Posted by JustAsIAm View Post
    Want to enlighten me?
    There is a series of 400+ JavaScript examples on the site that is the first link in my signature (the red one).
    Stephen J Chapman

    javascriptexample.net, Book Reviews, follow me on Twitter
    HTML Help, CSS Help, JavaScript Help, PHP/mySQL Help, blog
    <input name="html5" type="text" required pattern="^$">

  6. #6
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    felgall, thank you very much. I will be looking at that now.


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