Develop Reference

Grab all elements on a Page and hide a message in them

I'm trying to grab all the elements on my webpage using javascript. Once I do this I want to hide a message in the elements, probably by LSB. Right now I'm just trying to hide 'h' which would be 8 bits, which would require 8 elementIDs I think.
My plan is to grab all the IDs. Use charCodeAt to grab the value of 'h', then hide h's bits in the first 8 elementIDs using bitwise operations on the text size or width field.
I know this is an awful way to hide a message, but I really want to figure this out for learning purposes. Any ideas on how to do this, or direction would be awesome.
Here is what I have so far...
$(function() {
//on button click
// 1. grab LSB all of elements to be changed
// 2. change all elements
// str.charCodeAt(0);
//var arrayMsg = hideMsg.split("");
/*
// 1. maybe grab all elements on the page
// 2. make a special class with width and text
// 3. inject all element IDs with this class
// 4. flip this classes width/text size with LSB of message to hide
var allElements = document.getElementsByTagName("*");
var allIds = [];
for (var i = 0, n = allElements.length; i < n; ++i) {
var el = allElements[i];
if (el.id) { allIds.push(el.id); }
}
*/
var hideMsg = "f";
var n = hideMsg.length;
var i;
var j;
var holder;
var hideHolder;
// on button click - hide msg
$('#btnHide').on('click', function() {
for(i = 0; i < n; i++) {
//set var holder to first value of the message to hide
holder = hideMsg.charCodeAt(i);
for(j = 7; -1 < j; j--) {
//set hideHolder to holders value
hideHolder = holder;
//mask hideHolder to grab the first bit to hide
hideHolder = hideHolder & (1<<j);
//grab the first element ID
if(holder === 0) {
// embed the bit
// bitwise &=
} else {
//embed the bit
// bitwise ^=
}
}
}
});
});

Single-click only works once

I want to allow the user to remove words in a div by a single mouse click. It work fine, see jsFiddle.
The only problem is that the single-click feature only works on the first click. After that, you need to double click.
I can't get my head around why it is behaving like this. Maybe you can? Could be problem with jQuery(document).ready()...
jQuery:
// highlight a word/term quicker and smarter: so.com/a/35103840/1185126
jQuery(document).ready(function(e){
(function(els){
// variable declaration for previous range info
// and function for finding the sibling
var prevRangeInfo = {},
findSibling = function(thisNode, direction){
// get the child node list of the parent node
var childNodeList = thisNode.parentNode.childNodes,
children = [];
// convert the child node list to an array
for(var i=0, l=childNodeList.length; i<l; i++) children.push(childNodeList[i]);
return children[children.indexOf(thisNode) + direction];
};
for(var i=0;i<els.length;i++){
var el = els[i];
el.addEventListener('mouseup',function(evt){
if (document.createRange) { // Works on all browsers, including IE 9+
var selected = window.getSelection();
// Removing the following line from comments will make the function drag-only
/* if(selected.toString().length){ */
var d = document,
nA = selected.anchorNode,
oA = selected.anchorOffset,
nF = selected.focusNode,
oF = selected.focusOffset,
range = d.createRange(),
rangeLength = 0;
range.setStart(nA,oA);
range.setEnd(nF,oF);
// Check if direction of selection is right to left
if(range.startContainer !== nA || (nA === nF && oF < oA)){
range.setStart(nF,oF);
range.setEnd(nA,oA);
}
// Extend range to the next space or end of node
while(range.endOffset < range.endContainer.textContent.length && !/\s$/.test(range.toString())){
range.setEnd(range.endContainer, range.endOffset + 1);
}
// Extend range to the previous space or start of node
while(range.startOffset > 0 && !/^\s/.test(range.toString())){
range.setStart(range.startContainer, range.startOffset - 1);
}
// Remove spaces
if(/\s$/.test(range.toString()) && range.endOffset > 0)
range.setEnd(range.endContainer, range.endOffset - 1);
if(/^\s/.test(range.toString()))
range.setStart(range.startContainer, range.startOffset + 1);
// Store the length of the range
rangeLength = range.toString().length;
// Check if another range was previously selected
if(prevRangeInfo.startContainer && nA === nF && oA === oF){
var rangeTryContain = d.createRange(),
rangeTryLeft = d.createRange(),
rangeTryRight = d.createRange(),
nAp = prevRangeInfo.startContainer;
oAp = prevRangeInfo.startOffset;
nFp = prevRangeInfo.endContainer;
oFp = prevRangeInfo.endOffset;
rangeTryContain.setStart(nAp, oAp);
rangeTryContain.setEnd(nFp, oFp);
rangeTryLeft.setStart(nFp, oFp-1);
rangeTryLeft.setEnd(range.endContainer, range.endOffset);
rangeTryRight.setStart(range.startContainer, range.startOffset);
rangeTryRight.setEnd(nAp, oAp+1);
// Store range boundary comparisons
// & inner nodes close to the range boundary --> stores null if none
var compareStartPoints = range.compareBoundaryPoints(0, rangeTryContain) === 0,
compareEndPoints = range.compareBoundaryPoints(2, rangeTryContain) === 0,
leftInnerNode = range.endContainer.previousSibling,
rightInnerNode = range.startContainer.nextSibling;
// Do nothing if clicked on the right end of a word
if(range.toString().length < 1){
range.setStart(nAp,oAp);
range.setEnd(nFp,oFp);
}
// Collapse the range if clicked on last highlighted word
else if(compareStartPoints && compareEndPoints)
range.collapse();
// Remove a highlighted word from left side if clicked on
// This part is quite tricky!
else if(compareStartPoints){
range.setEnd(nFp,oFp);
if(range.startOffset + rangeLength + 1 >= range.startContainer.length){
if(rightInnerNode)
// there is a right inner node, set its start point as range start
range.setStart(rightInnerNode.firstChild, 0);
else {
// there is no right inner node
// there must be a text node on the right side of the clicked word
// set start of the next text node as start point of the range
var rightTextNode = findSibling(range.startContainer.parentNode, 1),
rightTextContent = rightTextNode.textContent,
level=1;
// if beginning of paragraph, find the first child of the paragraph
if(/^(?:\r\n|[\r\n])|\s{2,}$/.test(rightTextContent)){
rightTextNode = findSibling(rightTextNode, 1).firstChild;
level--;
}
range.setStart(rightTextNode, level);
}
}
else
range.setStart(range.startContainer, range.startOffset + rangeLength + 1);
}
// Remove a hightlighted word from right side if clicked on
// This part is also tricky!
else if (compareEndPoints){
range.setStart(nAp,oAp);
if(range.endOffset - rangeLength - 1 <= 0){
if(leftInnerNode)
// there is a right inner node, set its start point as range start
range.setEnd(leftInnerNode.lastChild, leftInnerNode.lastChild.textContent.length);
else {
// there is no left inner node
// there must be a text node on the left side of the clicked word
// set start of the previous text node as start point of the range
var leftTextNode = findSibling(range.endContainer.parentNode, -1),
leftTextContent = leftTextNode.textContent,
level = 1;
// if end of paragraph, find the last child of the paragraph
if(/^(?:\r\n|[\r\n])|\s{2,}$/.test(leftTextContent)){
leftTextNode = findSibling(leftTextNode, -1).lastChild;
level--;
}
range.setEnd(leftTextNode, leftTextNode.length - level);
}
}
else
range.setEnd(range.endContainer, range.endOffset - rangeLength - 1);
}
// Add previously selected range if adjacent
// Upgraded to include previous/next word even in a different paragraph
else if(/^[^\s]*((?:\r\n|[\r\n])|\s{1,})[^\s]*$/.test(rangeTryLeft.toString()))
range.setStart(nAp,oAp);
else if(/^[^\s]*((?:\r\n|[\r\n])|\s{1,})[^\s]*$/.test(rangeTryRight.toString()))
range.setEnd(nFp,oFp);
// Detach the range objects we are done with, clear memory
rangeTryContain.detach();
rangeTryRight.detach();
rangeTryLeft.detach();
}
// Save the current range --> not the whole Range object but what is neccessary
prevRangeInfo = {
startContainer: range.startContainer,
startOffset: range.startOffset,
endContainer: range.endContainer,
endOffset: range.endOffset
};
// Clear the saved range info if clicked on last highlighted word
if(compareStartPoints && compareEndPoints)
prevRangeInfo = {};
// Remove all ranges from selection --> necessary due to potential removals
selected.removeAllRanges();
// Assign the current range as selection
selected.addRange(range);
// Detach the range object we are done with, clear memory
range.detach();
el.style.MozUserSelect = '-moz-none';
// Removing the following line from comments will make the function drag-only
/* } */
} else {
// Fallback for Internet Explorer 8 and earlier
// (if you think it still is worth the effort of course)
}
});
/* This part is necessary to eliminate a FF specific dragging behavior */
el.addEventListener('mousedown',function(e){
if (window.getSelection) { // Works on all browsers, including IE 9+
var selection = window.getSelection ();
selection.collapse (selection.anchorNode, selection.anchorOffset);
} else {
// Fallback for Internet Explorer 8 and earlier
// (if you think it still is worth the effort of course)
}
el.style.MozUserSelect = 'text';
});
}
})(document.getElementsByClassName('taggable'));
});
// remove selected text
jQuery(document).ready(function() {
jQuery('.taggable').bind("mouseup", function() {
var text1;
if (window.getSelection().toString() != "") {
selectedText = window.getSelection().toString()
text1 = jQuery(".taggable").text().split("")
pointStart = window.getSelection().anchorOffset
pointEnd = window.getSelection().focusOffset
if (pointEnd < pointStart) {
pointStart = pointEnd
}
text1.splice(pointStart, selectedText.length);
text1 = text1.join("")
} else {
selectedText = jQuery(".taggable").text()
text1 = selectedText;
}
jQuery(".taggable").text(text1);
});
});

This might not solve your issue, but it's another approach.
This code wrap every word inside a span and create an event listener for each.
HTML
<p>This is an example text</p>
Javascript
jQuery(document).ready(function($) {
var text = $('p').text();
var arr = text.split(' ');
$('p').html('');
for (var i = 0; i < arr.length; i++) {
$('<span />').html(arr[i] + ' ').appendTo('p');
$('p').on('click', 'span:nth-of-type(' + (i + 1) + ')', function() {
$(this).remove();
});
}
});

I've figured out that the main problem is because if the anchorOffset is equal to focusOffset, it doesn't work, so, the possible solution is to add +1 when it's equal and then the code will work as desired since it finds at least a letter when substring. Change the code:
from
var selected = window.getSelection();
// Removing the following line from comments will make the function drag-only
/* if(selected.toString().length){ */
var d = document,
nA = selected.anchorNode,
oA = selected.anchorOffset,
nF = selected.focusNode,
oF = selected.focusOffset,
range = d.createRange(),
rangeLength = 0;
to
var selected = window.getSelection();
var offset = selected.focusOffset;
if(selected.anchorOffset == selected.focusOffset)
offset++;
// Removing the following line from comments will make the function drag-only
/* if(selected.toString().length){ */
var d = document,
nA = selected.anchorNode,
oA = selected.anchorOffset,
nF = selected.focusNode,
oF = offset,
range = d.createRange(),
rangeLength = 0;
I've tested many times here on JFiddle and it worked OK, but
I'm still afraid that this can result in some other problems.
If you get some problem, please notify me and i'll help.
EDIT:
jsFiddle

Javascript Markdown Parsing

I'm working on a markdown to html parser. I understand this is a big project and there are third party libraries, but none the less I want to roll a simple solution on my own that doesn't have to handle every single aspect of markdown.
So far the process is to take an input (in my case the value of a textarea) and parse it line by line.
var html = [];
var lines = txt.split('\n'); //Convert string to array
//Remove empty lines
for(var index = lines.length-1; index >= 0; index--) {
if(lines[index] == '') lines.splice(index, 1);
}
//Parse line by line
for(var index = 0; index <= lines.length-1; index++) {
var str = lines[index];
if(str.match(/^#[^#]/)) {
//Header
str = str.replace(/#(.*?)$/g, '<h1>$1</h1>');
} else if(str.match(/^##[^#]/)) {
//Header 2
str = str.replace(/##(.*?)$/g, '<h2>$1</h2>');
} else if(str.match(/^###[^#]/)) {
//Header 3
str = str.replace(/###(.*?)$/g, '<h3>$1</h3>');
} else if(str.trim().startsWith('+')) {
//Unordered List
var orig = str;
str = str.replace(/\+(.*?)$/, '<li>$1</li>');
var previous, next;
if(index > 0) previous = lines[index-1];
if(!previous || previous && previous.indexOf('+') < orig.indexOf('+')) {
str = '<ul>' + str;
}
if(index < lines.length-1) next = lines[index+1];
if(!next || next && next.indexOf('+') < orig.indexOf('+')) {
var count = Math.max(0, orig.indexOf('+') / 4);
if(next) count = count - Math.max(0, next.indexOf('+') / 4);
for(var i=1; i<=count; i++) {
str = str + '</ul>';
}
}
if(next && next.trim().indexOf('+') == -1) str = str + '</ul>';
} else if(str.match(/^[0-9a-zA-Z]/)) {
//Paragraph
str = str.replace(/^([0-9a-zA-Z].*?)$/g, '<p>$1</p>');
}
//Inline formatting
str = str.replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>'); //Bold
str = str.replace(/\_\_(.*?)\_\_/g, '<strong>$1</strong>'); //Another bold
str = str.replace(/\*(.*?)\*/g, '<em>$1</em>'); //Italics
str = str.replace(/\_(.*?)\_/g, '<em>$1</em>'); //Another italics
//Append formatted to return string
html.push(str);
}
Where I run into problems is with nested blocks such as ul. Currently the code looks at a line that starts with a + and wraps it in an li. Great, but these list items never get placed within a ul. I could run through the output again after the line by line and just wrap every group of li's, but that screws me up when I have nested li's that require their own ul.
Any thoughts on how to apply these additional wrapper tags? I've considered using my own special characters around list type elements so I know where to add the wrapper tags, but that breaks traditional markdown. I wouldn't be able to pass the raw markdown to someone other than myself and know they'd understand what was going on.
Edit I updated my code sample to include a working sample. The working sample also supports nested lists.

You need a very simple state machine.
When you encounter the first + you add <ul> and raise a flag.
If you don't see a line that starts with + and your flag is raised, then close the </ul>

Making individual letters in a string different colours

I'm trying to make the colour different for certain letters (if found) in a string eg. the letter i. The search count is working I just can't figure out the changing html colour of the individual letter.
I know if it was a whole word then I could just use split strings, but can't figure out how to do it for a single letter. I've found some examples, one that I have tried is at the bottom that is not working either.
//getMsg is another function, which passes in a user inputted string
function searchMsg(getMsg) {
alert (getMsg);
var msgBoxObject = document.getElementById('msgBox');
var pos = getMsg.indexOf('i')
var txtToFind = (document.getElementById('txtToFind').value);
var count = 0;
while (pos !== -1){
count++;
pos = getMsg.indexOf('i', pos + 1);
document.writeln (+count);
msgBoxObject.innerHTML = (count);
}
getMsg = getMsg.replace('/i/g<span class="red">i</span>');
document.writeln (getMsg);
}
Edit; I've added in this, but can't get the loop to work correctly so it displays all instances of the letter found instead of just one: /*while (pos !== -1){
count++;
pos = getMsg.indexOf('i', pos + 1);
document.writeln (+count);
msgBoxObject.innerHTML = (count);
}
*/
var count = 0; // Count of target value
var i = 0; // Iterative counter
// Examine each element.
for(i=0; i<arr.length; i++)
{ if(arr[i] == targetValue)
count++;
}
return count;
}
searchIndex = txtMsg.indexOf(txtToFind);
if (searchIndex >=0 ) {
// Copy text from phrase up till the match.
matchPhrase = txtMsg.slice(0, searchIndex);
matchPhrase += '<font color="red">' + txtToFind + '</font>';
matchPhrase += txtMsg.slice(searchIndex + txtToFind.length);
} else {
matchPhrase = "No matches"
}
displayProcessedMsg(matchPhrase);
document.writeln(matchPhrase);

You either need to add the corresponding css for that class or change the tag like #john_Smith specified
Adding the CSS
span.red {
color: red;
}
Changing the tag
On your code replace this
getMsg = getMsg.replace('/i/g<span class="red">i</span>');
for
getMsg = getMsg.replace('/i/g<span style:"color:red">i</span>');
Some example of inline css
Some advice on color palettes
Try looking into d3 color scales(https://github.com/mbostock/d3/wiki/Ordinal-Scales#categorical-colors) or apply a principle similar to incrementing an RGB value instead of using names of colors.
Hope this helps.

Ordering z-indexes in an array

I have an array which looks something along the lines of
resourceData[0][0] = "pic1.jpg";
resourceData[0][1] = 5;
resourceData[1][0] = "pic2.jpg";
resourceData[1][1] = 2;
resourceData[2][0] = "pic3.jpg";
resourceData[2][1] = 900;
resourceData[3][0] = "pic4.jpg";
resourceData[3][1] = 1;
The numeric represents the z-index of the image. Minimum z-index value is 1. Maximum (not really important) is 2000.
I have all the rendering and setting z-indexes done fine. My question is, I want to have four functions:
// Brings image to z front
function bringToFront(resourceIndex) {
// Set z-index to max + 1
resourceData[resourceIndex][1] = getBiggestZindex() + 1;
// Change CSS property of image to bring to front
$('#imgD' + resourceIndex).css("z-index", resourceData[resourceIndex][1]);
}
function bringUpOne(resourceIndex) {
}
function bringDownOne(resourceIndex) {
}
// Send to back z
function sendToBack(resourceIndex) {
}
So given then index [3] (900 z):
If we send it to the back, it will take the value 1, and [3] will have to go to 2, but that conflicts with [1] who has a 2 z-index so they need to go to three etc.
Is there an easy programatical way of doing this because as soon as I start doing this it's going to get messy.
It's important that the indexes of the array don't change. We can't sort the array unfortunately due to design.
Update
Thanks for answers, I'll post the functions here once they are written incase anyone comes across this in the future (note this code has zindex listed in [6])
// Send to back z
function sendToBack(resourceIndex) {
resourceData[resourceIndex][6] = 1;
$('#imgD' + resourceIndex).css("z-index", 1);
for (i = 0; i < resourceData.length; i++) {
if (i != resourceIndex) {
resourceData[i][6]++;
$('#imgD' + i).css("z-index", resourceData[i][6]);
}
}
}

Loops! This function will reorder affected images around it. It will work with images that have widely separated z-index values. It also does not perform any changes unless it needs to.
EDIT: added function to do the CSS work
EDIT 2: Corrected problem with top/bottom functions - it wasn't moving all the images affected, now it is.
var resourceData = Array();
resourceData[0] = Array();
resourceData[0][0] = "pic1.jpg";
resourceData[0][1] = 5;
resourceData[1] = Array();
resourceData[1][0] = "pic2.jpg";
resourceData[1][1] = 2;
resourceData[2] = Array();
resourceData[2][0] = "pic3.jpg";
resourceData[2][1] = 900;
resourceData[3] = Array();
resourceData[3][0] = "pic4.jpg";
resourceData[3][1] = 1;
function _doMoveImage(ptr) {
// Change CSS property of image
$('#imgD' + ptr).css("z-index", resourceData[ptr][1]);
}
// Brings image to z front
function bringToFront(resourceIndex) {
var highest_idx = 0;
for (var i = 0; i < resourceData.length; i++) {
// for all images except the target
if (i != resourceIndex) {
// preserve the highest index we encounter
if (highest_idx < resourceData[i][1])
highest_idx = resourceData[i][1];
// move any images higher than the target down by one
if (resourceData[i][1] > resourceData[resourceIndex][1]) {
resourceData[i][1]--;
_doMoveImage(i);
}
}
}
// now move the target to the highest spot, only if needed
if (resourceData[resourceIndex][1] < highest_idx) {
resourceData[resourceIndex][1] = highest_idx;
_doMoveImage(resourceIndex);
}
return;
}
function bringUpOne(resourceIndex) {
var next_idx = 2000;
var next_ptr = false;
for (var i =0; i < resourceData.length; i++) {
// for all images except the target
if (
i != resourceIndex &&
next_idx > resourceData[i][1] &&
resourceData[i][1] > resourceData[resourceIndex][1]
){
next_idx = resourceData[i][1];
next_ptr = i;
}
}
// only move if needed
if (next_ptr) {
// target takes next's index
resourceData[resourceIndex][1] = resourceData[next_ptr][1];
// next's index decreases by one
resourceData[next_ptr][1]--;
_doMoveImage(resourceIndex);
_doMoveImage(next_ptr);
}
return;
}
function bringDownOne(resourceIndex) {
var next_idx = 0;
var next_ptr = false;
for (var i =0; i < resourceData.length; i++) {
// for all images except the target
if (
i != resourceIndex &&
next_idx < resourceData[i][1] &&
resourceData[i][1] < resourceData[resourceIndex][1]
){
next_idx = resourceData[i][1];
next_ptr = i;
}
}
// only move if needed
if (next_ptr) {
// target takes next's index
resourceData[resourceIndex][1] = resourceData[next_ptr][1];
// next's index decreases by one
resourceData[next_ptr][1]++;
_doMoveImage(resourceIndex);
_doMoveImage(next_ptr);
}
}
// Send to back z
function sendToBack(resourceIndex) {
var lowest_idx = 2000;
for (var i = 0; i < resourceData.length; i++) {
// for all images except the target
if (i != resourceIndex) {
// preserve the lowest index we encounter
if (lowest_idx > resourceData[i][1])
lowest_idx = resourceData[i][1];
// move any images lower than the target up by one
if (resourceData[i][1] < resourceData[resourceIndex][1]) {
resourceData[i][1]++;
_doMoveImage(i);
}
}
}
// now move the target to the lowest spot, only if needed
if (resourceData[resourceIndex][1] > lowest_idx) {
resourceData[resourceIndex][1] = lowest_idx;
_doMoveImage(resourceIndex);
}
return;
}

There it is: copy your structure and have it properly ordered, or if you prefer call it indexed. When you need the picture find the proper z-index and proceed w/ the rendering.
You can do that dynamically and use heap, if you don't wish to copy the entire structure.

Not tested, but how about this. For bringUpOne, bringDownOne one you can swap the z-indexes, e.g:
function bringUpOne(resourceIndex) {
var myZIndex = resourceData[resourceIndex][1];
var nextZIndex = resourceData[resourceIndex + 1][1];
resourceData[resourceIndex][1] = nextZIndex;
resourceData[resourceIndex + 1][1] = myZindex;
}
For bringing to the front:
function bringToFront(resourceIndex) {
var maxZIndex = resourceData[maxResourceIndex][1];
resourceData[resourceIndex][1] = maxZIndex + 1;
}
Now that's all fine. But what happens if you want to successively set images to the back? You can either set the zIndex to 0 each time (don't know how many you'll have actually visiable at any time) or you can start with the lowest zIndex set to something like 2000 or 10000 or whatever, which will acccomodate many calls to setToBack.
Edit: This assumes the list is ordered by zIndex to start with.