I'm trying to ask the user through a prompt for a number that is an: integer, greater than 0, and is numeric. I did that with a do while loop and seems to be working correctly. With that number I have to pass it to the function called "genTable" and create a table with a dynamic amount of rows based on what the user typed. However, with my current code I can't seem to get the table to appear on the page. Any ideas on where I went wrong and how to fix it?
<!DOCTYPE HTML>
<html>
<head>
<title>jsLoopDemo</title>
<!--
Honor Code: I acknowledge that this code represents my own work: CC
Date: July 6, 2017
-->
<meta charset="utf-8" />
<meta name="description" content="Create a chart with rows based on a number
user chose." />
<meta name="keywords" content="loop, row, dynamic" />
<meta name="author" content="" />
<script type="text/javascript">
do{
var numChose = prompt("Please enter an interger greater than zero.");
}while (isNaN(numChose) || numChose % 1 !== 0 || numChose < 1 );
function genTable(numChose)
{
var table = document.createElement("TABLE");
var tableBody = document.createElement("TBODY");
table.appendChild(tableBody);
var myTableDiv = document.getElementById("mytable");
for (var r = 0; r <= numChose; r++)
{
var tr = document.createElement("TR");
tableBody.appendChild(tr);
var td = document.createElement("TD");
tr.appendChild(td);
td.appendChild(document.createTextNode("Row " + r));
}
myTableDiv.appendChild(table);
}
</script>
</head>
<body>
<div id="mytable">
</div>
</body>
</html>
Two things:
You need to actually call the function after the prompt, so you need to add a line after your do while:
genTable(numChose);
That still won't work, since the DOM will not be ready (myTableDiv will be undefined), so you need to wrap your entire code in an event listener:
document.addEventListener("DOMContentLoaded", function(event) {
//do work
});
Move the <script> code after the
<div id="mytable">
</div>
in <body> so that the element is rendered on DOM while table is being generated and call the function
genTable(numChose);
after you get the number from user.
Related
I have a table generated from a textarea filled by users, but some of the time, a cell stays empty (and that's all right).
The thing is that the .innerHTML of that cell is also my var y in a script and when that cell is empty (therefore, undefined), my var y becomes UNDEFINED too (the value, not a string), which makes my whole script fail.
Here's a snippet to show the problem:
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>
<body><center>
</center></body>
<!--------- script that generates my table from text areas -->
<script>
function generateTable() {
$('#excel_table1').html("");
var n=1;
var rows=[];
var lng=0;
var maxligne=0;
$('textarea').each(function(){
var data = $(this).val();
if (data !=''){
var rowData = data.split("\n");
rows[n] = rowData;
lng = rowData.length;
if(lng > maxligne)
{
maxligne=lng
}
n++;
}
}
)
var table = $('<table />');
k=0;
while (k < maxligne) {
var row = $('<tr />');
for(var i = 1; i < rows.length; i++)
{
var singleRow = rows[i];
if(singleRow[k]!= undefined){
row.append('<td>'+singleRow[k]+'</td>')
} else {
row.append('<td></td>')
}
}
table.append(row);
k++;
}
$('#excel_table1').append(table);
}
</script>
<textarea placeholder="data 2 Here" name="data1" style="width:100px;height:40px;"></textarea>
<textarea placeholder="data 2 Here" name="data2" style="width:200px;height:40px;"></textarea>
<textarea placeholder="fild not required" name="data3" style="width:200px;height:40px;"></textarea>
<br>
<input id=bouton1 type="button" onclick="javascript:generateTable()" value="GenerateTable"/>
<div id="excel_table1"></div>
<!--------- script that get the data from cells to show it in <H2> -->
<script type="text/javascript">
function buttonTEST()
{
$('#displayCell').html("");
var x = document.getElementById('excel_table1').getElementsByTagName('tr')[0].cells[1].innerHTML;
var y = document.getElementById('excel_table1').getElementsByTagName('tr')[0].cells[2].innerHTML;
if (y === undefined) {
y = " ";
}
document.getElementById('displayCell').innerHTML = x +" "+ y;
}
</script>
<br/><br/>
<h2 id="displayCell"></h2>
<br/><br/>
<input id="Button2" type="button" onclick="buttonTEST()" value="TEST ME"/>
As you can see, if you generate a table with only to columns (which is supposed/needs to happen sometimes), we get this error from the console because we're trying to get "innerHTML" from a undefined:
index.html:120 Uncaught TypeError: Cannot read property 'innerHTML' of undefined
A little specification: When that cell is=undefined , I need it to stay undefined, I only want to change the fact that my var y also becomes undefined.
So I thought that changing the value of var y (and not the value of that cell, otherwise, the 3rd column, supposed to be empty, would be created just because of an blank space) to a blank space would resolve the problem, but I don't seem to get it right (write it in a correct manner).
Any ideas?
Try
var x = document.getElementById('excel_table1').rows[0].cells[0].innerHTML;
var y = document.getElementById('excel_table1').rows[0].cells[1].innerHTML;
using rows instead of getElementsByTagName is cleaner.
Also note that the indexes for cells start from zero not 1, you probably only have 2 cells in your first row, but .cells[2].innerHTML tries to get the innerHTML of the 3rd cell which does not exist.
As others have pointed out, you're already using jQuery, so the easiest way to get the cell contents is to use a css selector to find the cells using the $ function, then call .html() to get the contents. A direct conversion of your current code to this approach could be:
var x = $('#excel_table1 tr:nth-child(1) td:nth-child(2)').html();
var y = $('#excel_table1 tr:nth-child(1) td:nth-child(3)').html();
This works in a way so that the $ function returns a jQuery object, which is essentially a set of elements, which can potentially be empty. Most jQuery functions are then designed to fail gracefully when called on an empty set. For instance, html will return undefined when invoked on an empty set, but it will not fail.
Note that it is not very robust to use the selector above, as it is obviously sensitive to the placement of the cells. It would be more maintainable to assign a class attribute to the cells that describes their content, and then select on that, e.g. something like
var name = $("#excel_table1 tr:nth-child(1) td.name").html()
So here's the answer that worked for me:
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>
<body><center>
</center></body>
<!--------- script that generates my table from text areas -->
<script>
function generateTable() {
$('#excel_table1').html("");
var n=1;
var rows=[];
var lng=0;
var maxligne=0;
$('textarea').each(function(){
var data = $(this).val();
if (data !=''){
var rowData = data.split("\n");
rows[n] = rowData;
lng = rowData.length;
if(lng > maxligne)
{
maxligne=lng
}
n++;
}
}
)
var table = $('<table />');
k=0;
while (k < maxligne) {
var row = $('<tr />');
for(var i = 1; i < rows.length; i++)
{
var singleRow = rows[i];
if(singleRow[k]!= undefined){
row.append('<td>'+singleRow[k]+'</td>')
} else {
row.append('<td></td>')
}
}
table.append(row);
k++;
}
$('#excel_table1').append(table);
}
</script>
<textarea placeholder="data 2 Here" name="data1" style="width:100px;height:40px;"></textarea>
<textarea placeholder="data 2 Here" name="data2" style="width:200px;height:40px;"></textarea>
<textarea placeholder="fild not required" name="data3" style="width:200px;height:40px;"></textarea>
<br>
<input id=bouton1 type="button" onclick="javascript:generateTable()" value="GenerateTable"/>
<div id="excel_table1"></div>
<!--------- script that get the data from cells to show it in <H2> -->
<script type="text/javascript">
function buttonTEST()
{
$('#displayCell').html("");
var x = $('#excel_table1 tr:nth-child(1) td:nth-child(2)').html();
var y = $('#excel_table1 tr:nth-child(1) td:nth-child(3)').html();
if (y ===undefined)
{document.getElementById('displayCell').innerHTML = x ;}
else
{document.getElementById('displayCell').innerHTML = x +" "+ y;}
}
</script>
<br/><br/>
<h2 id="displayCell"></h2>
<br/><br/>
<input id="Button2" type="button" onclick="buttonTEST()" value="TEST ME"/>
I've got the following problem:
I'm uploading a survey on amazon mturk using Python and the survey is done via HTML and javascript. I show one of three different versions of the survey to participants, which I select by generating a random number via javascript. I store the number in local storage to prevent refreshing the website from resetting it. The problem I find is that more people seem to get versions 1 than version 3. But I cannot recreate the problem for myself when running the code in Tryit Editor online.
Could you please help me understand (and fix) why this happens? The following is the (trimmed) HTML code that I upload. I replaced text and removed fluff.
<HTMLQuestion xmlns="http://mechanicalturk.amazonaws.com/AWSMechanicalTurkDataSchemas/2011-11-11/HTMLQuestion.xsd">
<HTMLContent><![CDATA[
<!-- YOUR HTML BEGINS -->
<!DOCTYPE html>
<html>
<head>
<meta http-equiv='Content-Type' content='text/html; charset=UTF-8'/>
<script type='text/javascript' src='https://s3.amazonaws.com/mturk-public/externalHIT_v1.js'></script>
<script>
function test(){
document.getElementById('txt-field').value = "1";
}
</script>
</head>
<body>
<form name='mturk_form' method='post' id='mturk_form' action='https://www.mturk.com/mturk/externalSubmit'><input type='hidden' value='' name='assignmentId' id='assignmentId'/>
<span>
<INPUT TYPE="text" NAME="link_click" id='txt-field' value="0" style="display: none">
<div><h3><a href="www.google.com" target="_blank" id='report420' onclick="test()" >link</a></h3>
Instructions</div>
<div><table border="1" style="height: 258px;" width="196"><tbody>Table</tbody></table></div>
</span>
<!--I think the relevant part starts here-->
<script>
document.write("Miscellaneous question");
var i = localStorage.getItem('i') || Math.floor(3*Math.random());
localStorage.setItem('i',i);
if (i==0){
document.write("Version 1");
}
if (i==1){
document.write("Version 2");
}
if (i==2){
document.write("Version 3");
}
document.write("Miscellaneous question");
</script>
<p><input type='submit' id='submitButton' value='Submit' /></p></form>
<script language='Javascript'>turkSetAssignmentID();</script>
</body></html>
<!-- YOUR HTML ENDS -->
]]>
</HTMLContent>
<FrameHeight>600</FrameHeight>
</HTMLQuestion>
The random function Math.floor(3*Math.random()) has uniform distribution, but I don't think that 400 samples are enough so that you can see it in action (as #desoares mentioned).
Testing code:
var count = [0, 0, 0];
var n = 1000000;
document.write('Testing for ' + n + ' samples : ');
for (var i = 0; i < n; i++) {
count[Math.floor(3*Math.random())]++;
}
document.write(JSON.stringify(count));
var count = [0, 0, 0];
var n = 400;
document.write('Testing for ' + n + ' samples : ');
for (var i = 0; i < n; i++) {
count[Math.floor(3*Math.random())]++;
}
document.write(JSON.stringify(count));
Also, if you want to be sure that people from the same computer are not forced to take the same version, you should clear the saved variable localStorage.removeItem('i'); on submit. You may also add an expiration mechanic.
I have the code below that returns the rowIndex of the clicked row.
The table uses the info from the WebViewString element, it has an csv formatted data and always have at least one column.
I need to get the value of the first column of that row. How to???
I know nothing about JS... just need this little modification but couldn't find anything by myself.
<!doctype html>
<head>
<meta name="author" content="puravidaapps.com">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=0">
<!--Import materialize.css-->
<link type="text/css" rel="stylesheet" href="materialize.min.css" media="screen,projection"/>
<title>Table Layout</title>
</head>
<body>
<div id="myTable"></div>
<script>
// if you have commas inside your text, feel free to use another delimiter, for example |
var delimiter = ",";
// get the table to display from the window.AppInventor object and split at new line
var urlArray = window.AppInventor.getWebViewString().split("\n");
//var urlArray = location.search.slice(1).split("/n");
var doc = document;
var fragment = doc.createDocumentFragment();
var thead = doc.createElement("thead");
var tr = doc.createElement("tr");
// split at delimiter
var rowArray = urlArray[0].split(delimiter);
addRow(thead, "th");
fragment.appendChild(thead);
var tbody = doc.createElement("tbody");
for(i=1;i<urlArray.length;i++){
var tr = doc.createElement("tr");
// split at delimiter
var rowArray = urlArray[i].split(delimiter);
tr.addEventListener ("click", function () {
// return index (add 1 because first row is the header row)
// window.document.title = this.rowIndex + 1;
window.AppInventor.setWebViewString(this.rowIndex + 1);
});
addRow(tbody, "td");
}
fragment.appendChild(tbody);
var table = doc.createElement("table");
table.appendChild(fragment);
doc.getElementById("myTable").appendChild(table);
// http://stackoverflow.com/a/9236195/1545993
doc.getElementById("myTable").getElementsByTagName('table')[0].className = "striped";
function addRow(dom, tag) {
for(j=0;j<rowArray.length;j++){
var el = doc.createElement(tag);
el.innerHTML = rowArray[j];
tr.appendChild(el);
dom.appendChild(tr);
}
}
</script>
</body>
</html>
<!DOCTYPE html PUBLIC "-//w3c//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns = "http://www.w3.org/1999/xhtml">
<head>
<title> Mrudul Patel </title>
<script>
function myFunction() //function to create table based on user inputted rows and columns
{
var rows = prompt("Please enter number of rows", ""); //create prompt for rows
var columns = prompt("Please enter number of columns",""); //create prompt for columns
var table = document.createElement('table');
var table2 = document.getElementById('taskname').value;
for (var r = 0; r < rows; r++)
{
rows = table.insertRow(-1);
for (car c = 0; c < columns; c++)
{
columns = rows.insertCell(-1);
columns.appendChild(document.createTextNode(taskName));
}
}
document.getElementById('holdTable').appendChild(table);
};
</script>
</head>
<body>
<p>Click "Try it" button for prompt for rows and column</p>
<button onlick="myFuction()"> Try it </button>
<p id="Begin"></p>
</body>
</html>
Most of the script was copied from the example I found here but I'm unable to create table based on what I have. All I get is my text and the button mention in body tag.
Any help is appreciated. Again, I just need help with function so that the function creates the table based on user prompted rows and columns.
Thanks in advance!
How would you start writing a for loop for the code provided below:
<html>
<head>
</head>
<body>
Rows: <input name="rows" id="rows" type="text"/><br/>
<input type="submit" value="Make me a table!" onclick="makeTable();"/><br/><br/>
<table border="1" id="theTable">
</table>
<script type="text/javascript">
function makeTable(){
//Insert code here AND ONLY HERE!
//Write a for loop to create the number of rows specified in the "row" input field
</script>
</body>
</html>
As I suspect this is homework I will no provider a full code answer but instead provide you with a few guide lines that hopefully will help you.
You have the html and the javascript, in order to create new html elements you need to use the document.createElement(type) function that will create a new element, in your case - td/th ?
Then you need to insert it into your table
You do that by obtaining the table(by id/type) - search the web for this one its very simple.
And then using the append method on is with the created element.
You do all this process with a normal for loop that will run until the .value of the input tags you have in your html (Again, search for how to obtain these values)
Good luck =]
Is this what you are looking for?
function makeTable(){
// Get values of rows/cols inputs
var rows = document.getElementById('rows').value;
var cols = document.getElementById('cols').value;
// Check the values are in fact numbers
if (!isNaN(rows) && !isNaN(cols)) {
// Get the table element
var table = document.getElementById('theTable');
// Iterate through rows
for (var r = 0; r < rows; ++r) {
// Create row element
var tr = document.createElement('tr');
// Iterate through columns
for (var c = 0; c < cols; ++c) {
// Create cell element
var td = document.createElement('td');
// Setting some text content
td.textContent = 'R: ' + r + ', C: ' + c;
// Append cell to row
tr.appendChild(td);
}
// Append row to table
table.appendChild(tr);
}
}
}
<!DOCTYPE html>
<html>
<head>
<title>test</title>
<script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
</head>
<body>
Rows: <input name="rows" id="rows" type="text"/><br/>
Cols: <input name="cols" id="cols" type="text"/><br/>
<input type="submit" value="Make me a table!" onclick="makeTable();"/> <br/><br/>
<table border="1" id="theTable">
<script type="text/javascript">
function makeTable(){
var html = "";
var row=$('#rows').val();
var col=$('#cols').val();
for(var i=0; i<row; i++){
html+="<tr>";
for(var j=0;j<col; j++)
{
html+= '<td> Your data </td>';
}
html+="</tr>"
}
$('#theTable').html(html);
//Insert code here AND ONLY HERE!
//Write a for loop to create the number of rows specified in the "row" input field
//create a dom element for the row to be added to the table
}
</script>
</body>
</html>
I have kept it simple. Hope it helps.