Untitled

<html>
    <head>
        <title>Page Layout</title>
<!--
    The number of lines that can be printed on a paper depends on the paper size,
    the point size of each character in a line, whether lines are double-spaced or
    single-spaced, the top and bottom margin, and the left and right margins of the
    paper. Assume that all characters are of the same point size, and all lines are either
    single-spaced or double-spaced. Note that 1 inch=72 points. Moreover, assume that the
    lines are printed along the width of the paper. For example, if the length of the paper
    is 11 inches and width is 8.5 inches, then the maximum length of a line is 8.5 inches.
    Write a program that calculates the number of characters in a line and the number of lines
    that can be printed on a paper based on the following input from the user:
    a. The lenght and width, in inches of the paper
    b. The top, bottom, left and right margins
    c. The point size of a line
    d. If the lines are double-spaced, then double the point size of each character
-->
        <script type="text/javascript">
            function elid(id){
                return document.getElementById(id);
            }
            function formFloat(id){
                var input = elid(id).value;
                var num = parseFloat(input);
                if(input != num){
                    alert(id.substr(0,1).toUpperCase() + id.substr(1) + ' needs to be a number');
                    errors++;
                    return false;
                }else{
                    return num;
                }
            }
            function Calculate(){
                errors = 0;
                var width = formFloat('width');
                var length = formFloat('length');
                var top = formFloat('top');
                var bottom = formFloat('bottom');
                var left = formFloat('left');
                var right = formFloat('right');
                var font = formFloat('font');
                var spacing = formFloat('spacing');

                if(errors === 0){
                    var hMar = left + right;
                    var vMar = top + bottom;
                    var hSpace = width - hMar;
                    var vSpace = length - vMar;
                    var charsPerLine = Math.floor(hSpace / (font/72));
                    var linesPerPage = Math.floor(vSpace / ((font/72) * spacing));
                    var charsPerPage = charsPerLine * linesPerPage;
                }else{
                    var charsPerLine = linesPerPage = charsPerPage = 'Errors In The Input';
                }
                elid("cline").value = charsPerLine;
                elid("lpage").value = linesPerPage;
                elid("cpage").value = charsPerPage;
            }
            var errors = 0;
        </script>
    </head>
<body>
    <form id='frm'>
        <table border="0">
            <tr>
                <th colspan="2"> Paper Size (inches)</th>
            </tr>
            <tr>
                <td> Width</td>
                <td><input type="text" id="width"></td>
            </tr>
            <tr>
                <td> Length</td>
                <td> <input type="text" id="length"></td>
            </tr>
            <tr>
                <th colspan=2> Margins (inches) </th>
            </tr>
            <tr>
                <td> Top </td>
                <td> <input type="text" id="top"></td>
            </tr>
            <tr>
                <td> Bottom </td>
                <td> <input type="text" id="bottom"></td>
            </tr>
            <tr>
                <td> Left </td>
                <td> <input type="text" id="left"></td>
            </tr>
            <tr>
                <td> Right </td>
                <td> <input type="text" id="right"></td>
            </tr>
            <tr>
                <th colspan=2> Formatting </th>
            </tr>
            <tr>
                <td> Font Size (pt) </td>
                <td> <input type="text" id="font"></td>
            </tr>
            <tr>
                <td> Line Spacing </td>
                <td>
                    <select id="spacing">
                        <option value="1" selected> Single </option>
                        <option value="2"> Double </option>
                    </select>
                </td>
            </tr>
            <tr>
                <td colspan=2><center> <input type="button" value="Calculate" onclick="Javascript: Calculate();"> </center> </td>
            </tr>
        </table>
        <br><br>
        <table border="0">
            <tr>
                <td> No. of Characters in a Line </td>
                <td> <input type="text" id="cline"> </td>
            </tr>
            <tr>
                <td> No. of Lines on a Page </td>
                <td> <input type="text" id="lpage"> </td>
            </tr>
            <tr>
                <td> Characters per Page</td>
                <td> <input type="text" id="cpage"> </td>
            </tr>
        </table>
    </form>
</body>
<html>