Calculating text selection offsets in nest elements in Javascript - javascript

The Problem
I am trying to figure out the offset of a selection from a particular node with javascript.
Say I have the following HTML
<p>Hi there. This <strong>is blowing my mind</strong> with difficulty.</p>
If I select from blowing to difficulty, it gives me the offset from the #text node inside of the <strong>. I need the string offset from the <p>'s innerHTML and the length of the selection. In this case, the offset would be 26 and the length would be 40.
My first thought was to do something with string offsets, etc. but you could easily have something like
<p> Hi there. This <strong>is awesome</strong>. For real. It <strong>is awesome</strong>.</p>
which would break that method because there are identical nodes. I also need the option to throw out nodes. Say I have something like this
<p>Hi there. This <strong>is blowing my mind</strong> with difficulty.</p>
I want to throw out an elements with rel="inserted" when I do the calculation. I still want 26 and 40 as the result.
What I'm looking for
The solution needs to be recursive. If there was a <span> with a <strong> in it, it would still need to traverse to the <p>.
The solution needs to remove the length of any element with rel="inserted". The contents are important, but the tags themselves are not. All other tags are important. I'd strongly prefer not to remove any elements from the DOM when I do all of this.
I am using document.getSelection() to get the selection object. This solution only has to work in WebKit. jQuery is an option, but I'd prefer to it without it if possible.
Any ideas would be greatly appreciated.
I have no control over the HTML I doing all of this on.

I think I solved my issue. I ended not calculating the offset like I originally planned. I am storing the "path" from the chunk (aka <p>). Here is the code:
function isChunk(node) {
if (node == undefined || node == null) {
return false;
}
return node.nodeName == "P";
}
function pathToChunk(node) {
var components = new Array();
// While the last component isn't a chunk
var found = false;
while (found == false) {
var childNodes = node.parentNode.childNodes;
var children = new Array(childNodes.length);
for (var i = 0; i < childNodes.length; i++) {
children[i] = childNodes[i];
}
components.unshift(children.indexOf(node));
if (isChunk(node.parentNode) == true) {
found = true
} else {
node = node.parentNode;
}
}
return components.join("/");
}
function nodeAtPathFromChunk(chunk, path) {
var components = path.split("/");
var node = chunk;
for (i in components) {
var component = components[i];
node = node.childNodes[component];
}
return node;
}
With all of that, you can do something like this:
var p = document.getElementsByTagName('p')[0];
var piece = nodeAtPathFromChunk(p, "1/0"); // returns desired node
var path = pathToChunk(piece); // returns "1/0"
Now I just need to expand all of that to support the beginning and the end of a selection. This is a great building block though.

What does this offset actually mean? An offset within the innerHTML of an element is going to be extremely fragile: any insertion of a new node or change to an attribute of an element preceding the point in the document the offset represents is going to make that offset invalid.
I strongly recommend using the browser's built-in support for this in the form of DOM Range. You can get hold of a range representing the current selection as follows:
var range = window.getSelection().getRangeAt(0);
If you're going to be manipulating the DOM based on this offset that you want, you're best off doing so using nodes instead of string representations of those nodes.

you can use the following java script code:
var text = window.getSelection();
var start = text.anchorOffset;
alert(start);
var end = text.focusOffset - text.anchorOffset;
alert(end);

Just check if your selected element is a paragraph, and if not use something like Prototype's Element.up() method to select the first paragraph parent.
For example:
if(selected_element.nodeName != 'P') {
parent_paragraph = $(selected_element).up('p');
}
Then just find the difference between the parent_paragraph's text offset and your selected_element's text offset.

Maybe you could use the jQuery selectors to ignore the rel="inserted"?
$('a[rel!=inserted]').doSomething();
http://api.jquery.com/attribute-not-equal-selector/
What code are you using now to select from blowing to difficulty?

Related

Changing the background color of text on a webpage in JavaScript (when element ID or name isn't available)

What I want to achieve is that once a web page is loaded, find some text in it and highlight the text. My code what I've written till now is as follows.
First I match the textContent using a regular expression
(Why am I using this approach is because I don't have the ID or name for the div where the textContent is present, thus, I cant go for getElementsByName() or getElementById()). To check if the text exists, I first compare it's length and then proceed to highlight it.
The text I find is at index 0 of the text variable. I cant access backgroundColor() method that is why it's been commented out for now. I could access fontcolor() but even it didn't seem to work.
I am new to JS so some direction would be greatly appreciated.
I would like to know why fontcolor() doesn't work even though I can access it.
What would be the best approach to solve this as I cant access backgroundColor().
(function highlightText(){
let text = document.body.textContent.match(/abcxyz/);
if (text[0].length == 6)
{
text[0].fontcolor('yellow');
//text[0].backgroundColor('yellow');
console.log(text[0]); //prints abcxyz
return text[0];
}
return null;
})()
SOLUTION:
The approach based off on the solution provided by #forlen:
What I did was loop through all the nodes, if the textContent matches the regular expression then push them into an array and as I knew what I wanted was the root element so I got the last element of the array and changed its backgroundColor.
(function highlightText() {
let allNodes = document.body.getElementsByTagName("*");
var arr= [];
for (let node of allNodes) {
if (node.textContent.match(/abcxyz/)) {
arr.push(node);
}
}
text = arr[(arr.length)-2];
text.style.backgroundColor = "yellow";
})();
I recommend looping through all nodes in body and changing style like this:
(function highlightText() {
let allNodes = document.body.getElementsByTagName("*");
for (let node of allNodes) {
if (node.textContent === "abcxyz") {
node.style.color = "yellow";
}
}
})();

How to limit Javascript's window.find to a particular DIV?

Is it possible to use Javascript in Safari/Firefox/Chrome to search a particular div container for a given text string. I know you can use window.find(str) to search the entire page but is it possible to limit the search area to the div only?
Thanks!
Once you look up your div (which you might do via document.getElementById or any of the other DOM functions, various specs here), you can use either textContent or innerText to find the text of that div. Then you can use indexOf to find the string in that.
Alternately, at a lower level, you can use a recursive function to search through all text nodes in the window, which sounds a lot more complicated than it is. Basically, starting from your target div (which is an Element), you can loop through its childNodes and search their nodeValue string (if they're Texts) or recurse into them (if they're Elements).
The trick is that a naive version would fail to find "foo" in this markup:
<p><span>fo</span>o</p>
...since neither of the two Text nodes there has a nodeValue with "foo" in it (one of them has "fo", the other "o").
Depending on what you are trying to do, there is an interesting way of doing this that does work (does require some work).
First, searching starts at the location where the user last clicked. So to get to the correct context, you can force a click on the div. This will place the internal pointer at the beginning of the div.
Then, you can use window.find as usual to find the element. It will highlight and move toward the next item found. You could create your own dialog and handle the true or false returned by find, as well as check the position. So for example, you could save the current scroll position, and if the next returned result is outside of the div, you restore the scroll. Also, if it returns false, then you can say there were no results found.
You could also show the default search box. In that case, you would be able to specify the starting position, but not the ending position because you lose control.
Some example code to help you get started. I could also try putting up a jsfiddle if there is enough interest.
Syntax:
window.find(aStringToFind, bCaseSensitive, bBackwards, bWrapAround, bWholeWord, bSearchInFrames, bShowDialog);
For example, to start searching inside of myDiv, try
document.getElementById("myDiv").click(); //Place cursor at the beginning
window.find("t", 0, 0, 0, 0, 0, 0); //Go to the next location, no wrap around
You could set a blur (lose focus) event handler to let you know when you leave the div so you can stop the search.
To save the current scroll position, use document.body.scrollTop. You can then set it back if it trys to jump outside of the div.
Hope this helps!
~techdude
As per the other answer you won't be able to use the window.find functionality for this. The good news is, you won't have to program this entirely yourself, as there nowadays is a library called rangy which helps a lot with this. So, as the code itself is a bit too much to copy paste into this answer I will just refer to a code example of the rangy library that can be found here. Looking in the code you will find
searchScopeRange.selectNodeContents(document.body);
which you can replace with
searchScopeRange.selectNodeContents(document.getElementById("content"));
To search only specifically in the content div.
If you are still looking for someting I think I found a pretty nice solution;
Here it is : https://www.aspforums.net/Threads/211834/How-to-search-text-on-web-page-similar-to-CTRL-F-using-jQuery/
And I'm working on removing jQuery (wip) : codepen.io/eloiletagant/pen/MBgOPB
Hope it's not too late :)
You can make use of Window.find() to search for all occurrences in a page and Node.contains() to filter out unsuitable search results.
Here is an example of how to find and highlight all occurrences of a string in a particular element:
var searchText = "something"
var container = document.getElementById("specificContainer");
// selection object
var sel = window.getSelection()
sel.collapse(document.body, 0)
// array to store ranges found
var ranges = []
// find all occurrences in a page
while (window.find(searchText)) {
// filter out search results outside of a specific element
if (container.contains(sel.anchorNode)){
ranges.push(sel.getRangeAt(sel.rangeCount - 1))
}
}
// remove selection
sel.collapseToEnd()
// Handle ranges outside of the while loop above.
// Otherwise Safari freezes for some reason (Chrome doesn't).
if (ranges.length == 0){
alert("No results for '" + searchText + "'")
} else {
for (var i = 0; i < ranges.length; i++){
var range = ranges[i]
if (range.startContainer == range.endContainer){
// Range includes just one node
highlight(i, range)
} else {
// More complex case: range includes multiple nodes
// Get all the text nodes in the range
var textNodes = getTextNodesInRange(
range.commonAncestorContainer,
range.startContainer,
range.endContainer)
var startOffset = range.startOffset
var endOffset = range.endOffset
for (var j = 0; j < textNodes.length; j++){
var node = textNodes[j]
range.setStart(node, j==0? startOffset : 0)
range.setEnd(node, j==textNodes.length-1?
endOffset : node.nodeValue.length)
highlight(i, range)
}
}
}
}
function highlight(index, range){
var newNode = document.createElement("span")
// TODO: define CSS class "highlight"
// or use <code>newNode.style.backgroundColor = "yellow"</code> instead
newNode.className = "highlight"
range.surroundContents(newNode)
// scroll to the first match found
if (index == 0){
newNode.scrollIntoView()
}
}
function getTextNodesInRange(rootNode, firstNode, lastNode){
var nodes = []
var startNode = null, endNode = lastNode
var walker = document.createTreeWalker(
rootNode,
// search for text nodes
NodeFilter.SHOW_TEXT,
// Logic to determine whether to accept, reject or skip node.
// In this case, only accept nodes that are between
// <code>firstNode</code> and <code>lastNode</code>
{
acceptNode: function(node) {
if (!startNode) {
if (firstNode == node){
startNode = node
return NodeFilter.FILTER_ACCEPT
}
return NodeFilter.FILTER_REJECT
}
if (endNode) {
if (lastNode == node){
endNode = null
}
return NodeFilter.FILTER_ACCEPT
}
return NodeFilter.FILTER_REJECT
}
},
false
)
while(walker.nextNode()){
nodes.push(walker.currentNode);
}
return nodes;
}
For the Range object, see https://developer.mozilla.org/en-US/docs/Web/API/Range.
For the TreeWalker object, see https://developer.mozilla.org/en-US/docs/Web/API/TreeWalker
var elements = [];
$(document).find("*").filter(function () {
if($(this).text().contains(yourText))
elements.push($(this));
});
console.log(elements);
I didn't try it, but according the jQuery documentation it should work.
Here is how I am doing with jquery:
var result = $('#elementid').text().indexOf('yourtext') > -1
it will return true or false
Maybe you are trying to not use jquery...but if not, you can use this $('div:contains(whatyouarelookingfor)') the only gotcha is that it could return parent elements that also contain the child div that matches.

Regex to search html return, but not actual html jQuery

I'm making a highlighting plugin for a client to find things in a page and I decided to test it with a help viewer im still building but I'm having an issue that'll (probably) require some regex.
I do not want to parse HTML, and im totally open on how to do this differently, this just seems like the the best/right way.
http://oscargodson.com/labs/help-viewer
http://oscargodson.com/labs/help-viewer/js/jquery.jhighlight.js
Type something in the search... ok, refresh the page, now type, like, class or class=" or type <a you'll notice it'll search the actual HTML (as expected). How can I only search the text?
If i do .text() it'll vaporize all the HTML and what i get back will just be a big blob of text, but i still want the HTML so I dont lose formatting, links, images, etc. I want this to work like CMD/CTRL+F.
You'd use this plugin like:
$('article').jhighlight({find:'class'});
To remove them:
.jhighlight('remove')
==UPDATE==
While Mike Samuel's idea below does in fact work, it's a tad heavy for this plugin. It's mainly for a client looking to erase bad words and/or MS Word characters during a "publishing" process of a form. I'm looking for a more lightweight fix, any ideas?
You really don't want to use eval, mess with innerHTML or parse the markup "manually". The best way, in my opinion, is to deal with text nodes directly and keep a cache of the original html to erase the highlights. Quick rewrite, with comments:
(function($){
$.fn.jhighlight = function(opt) {
var options = $.extend($.fn.jhighlight.defaults, opt)
, txtProp = this[0].textContent ? 'textContent' : 'innerText';
if ($.trim(options.find.length) < 1) return this;
return this.each(function(){
var self = $(this);
// use a cache to clear the highlights
if (!self.data('htmlCache'))
self.data('htmlCache', self.html());
if(opt === 'remove'){
return self.html( self.data('htmlCache') );
}
// create Tree Walker
// https://developer.mozilla.org/en/DOM/treeWalker
var walker = document.createTreeWalker(
this, // walk only on target element
NodeFilter.SHOW_TEXT,
null,
false
);
var node
, matches
, flags = 'g' + (!options.caseSensitive ? 'i' : '')
, exp = new RegExp('('+options.find+')', flags) // capturing
, expSplit = new RegExp(options.find, flags) // no capturing
, highlights = [];
// walk this wayy
// and save matched nodes for later
while(node = walker.nextNode()){
if (matches = node.nodeValue.match(exp)){
highlights.push([node, matches]);
}
}
// must replace stuff after the walker is finished
// otherwise replacing a node will halt the walker
for(var nn=0,hln=highlights.length; nn<hln; nn++){
var node = highlights[nn][0]
, matches = highlights[nn][1]
, parts = node.nodeValue.split(expSplit) // split on matches
, frag = document.createDocumentFragment(); // temporary holder
// add text + highlighted parts in between
// like a .join() but with elements :)
for(var i=0,ln=parts.length; i<ln; i++){
// non-highlighted text
if (parts[i].length)
frag.appendChild(document.createTextNode(parts[i]));
// highlighted text
// skip last iteration
if (i < ln-1){
var h = document.createElement('span');
h.className = options.className;
h[txtProp] = matches[i];
frag.appendChild(h);
}
}
// replace the original text node
node.parentNode.replaceChild(frag, node);
};
});
};
$.fn.jhighlight.defaults = {
find:'',
className:'jhighlight',
color:'#FFF77B',
caseSensitive:false,
wrappingTag:'span'
};
})(jQuery);
If you're doing any manipulation on the page, you might want to replace the caching with another clean-up mechanism, not trivial though.
You can see the code working here: http://jsbin.com/anace5/2/
You also need to add display:block to your new html elements, the layout is broken on a few browsers.
In the javascript code prettifier, I had this problem. I wanted to search the text but preserve tags.
What I did was start with HTML, and decompose that into two bits.
The text content
Pairs of (index into text content where a tag occurs, the tag content)
So given
Lorem <b>ipsum</b>
I end up with
text = 'Lorem ipsum'
tags = [6, '<b>', 10, '</b>']
which allows me to search on the text, and then based on the result start and end indices, produce HTML including only the tags (and only balanced tags) in that range.
Have a look here: getElementsByTagName() equivalent for textNodes.
You can probably adapt one of the proposed solutions to your needs (i.e. iterate over all text nodes, replacing the words as you go - this won't work in cases such as <tag>wo</tag>rd but it's better than nothing, I guess).
I believe you could just do:
$('#article :not(:has(*))').jhighlight({find : 'class'});
Since it grabs all leaf nodes in the article it would require valid xhtml, that is, it would only match link in the following example:
<p>This is some paragraph content with a link</p>
DOM traversal / selector application could slow things down a bit so it might be good to do:
article_nodes = article_nodes || $('#article :not(:has(*))');
article_nodes.jhighlight({find : 'class'});
May be something like that could be helpful
>+[^<]*?(s(<[\s\S]*?>)?e(<[\s\S]*?>)?e)[^>]*?<+
The first part >+[^<]*? finds > of the last preceding tag
The third part [^>]*?<+ finds < of the first subsequent tag
In the middle we have (<[\s\S]*?>)? between characters of our search phrase (in this case - "see").
After regular expression searching you could use the result of the middle part to highlight search phrase for user.

Get all DOM block elements for selected texts

When selecting texts in HTML documents, one can start from within one DOM element to another element, possibly passing over several other elements on the way. Using DOM API, it is possible to get the range of the selection, the selected texts, and even the parent element of all those selected DOM elements (using commonAncestorContainer or parentElement() based on the used browser). However, there is no way I am aware of that can list all those containing elements of the selected texts other than getting the single parent element that contains them all. Using the parent and traversing the children nodes won't do it, as there might be other siblings which are not selected inside this parent.
So, is there is a way that I can get all these elements that contains the selected texts. I am mainly interested in getting the block elements (p, h1, h2, h3, ...etc) but I believe if there is a way to get all the elements, then I can go through them and filter them to get what I want. I welcome any ideas and suggestions.
Thank you.
Key is window.getSelection().getRangeAt(0) https://developer.mozilla.org/en/DOM/range
Here's some sample code that you can play with to do what you want. Mentioning what you really want this for in question will help people provide better answers.
var selection = window.getSelection();
var range = selection.getRangeAt(0);
var allWithinRangeParent = range.commonAncestorContainer.getElementsByTagName("*");
var allSelected = [];
for (var i=0, el; el = allWithinRangeParent[i]; i++) {
// The second parameter says to include the element
// even if it's not fully selected
if (selection.containsNode(el, true) ) {
allSelected.push(el);
}
}
console.log('All selected =', allSelected);
This is not the most efficient way, you could traverse the DOM yourself using the Range's startContainer/endContainer, along with nextSibling/previousSibling and childNodes.
You can use my Rangy library to do this. It provides an implementation of DOM Range and Selection objects for all browsers, including IE, and has extra Range methods. One of these is getNodes():
function isBlockElement(el) {
// You may want to add a more complete list of block level element
// names on the next line
return /h[1-6]|div|p/i.test(el.tagName);
}
var sel = rangy.getSelection();
if (sel.rangeCount) {
var range = sel.getRangeAt(0);
var blockElements = range.getNodes([1], isBlockElement);
console.log(blockElements);
}
It sounds like you could use Traversing from the jQuery API.
Possibly .contents()
Hope that helps!
Here is a es6 approach based on #Juan Mendes response:
const selection = window.getSelection();
const range = selection.getRangeAt(0);
const elementsFromAncestorSelections = range.commonAncestorContainer.getElementsByTagName("*");
const allSelectedElements = Array.from(elementsFromAncestorSelections).reduce(
(elements, element) =>
selection.containsNode(element, true)
? [...elements, element]
: elements,
[],
);

How do I get element's className inside loop of elements?

I am trying to create a function that given a divid, and a list of classes, will then do some text replacing inside them.
Having learned of how Firefox Dom is handling text nodes differently, I read that I had to use javascript to loop through the elements, sibling to nextSibling.
The last obstacle I had in my script, of which you see a small portion of, is getting the classname. I need the class name so that I can filter down what content get's text replaced.
Having looked all the answers, and with the help of a co-worker named Ryan at work, we have redone this in jquery.
$(divid).find(".status_bar").each( function() {
var value = $.trim($(this).text());
// if value is not defined thru browser bugs do not replace
if (typeof(value) != 'undefined') {
// it is a text node. do magic.
for (var x = en_count; x > 0; x--) {
// get current english phrase
var from = en_lang[x];
// get current other language phrase
var to = other_lang[x];
if (value == from) {
console.log('Current Value ['+value+'] English ['+from+'] Translation ['+to+']');
value = to;
$(this).attr('value', to);
}
}
}
});
This currently works in all areas, except in the replacing of text.
The reason I had originally with doing this in jQuery, had to be not sure I could loop thru elements, and avoid the problem with firefox and text nodes.
I am doing a loop of all elements inside a div, and I now need to get the classname of the element that I am looping by.
Then i can check if the current element's class is one, I need to do something with...
// var children = parent.childNodes, child;
var parentNode = divid;
// start loop thru child nodes
for(var node=parentNode.firstChild;node!=null;node=node.nextSibling){
var myclass = (node.className ? node.className.baseVal : node.getAttribute('class'));
}
But this code for getting the classname only get's null values.
Any suggestions?
For those of you who are trying to figure out what the whole point is, read this JavaScript NextSibling Firefox Bug Fix I have code that does my language translation that works in Google Chrome and IE. But when I use it in Firefox, and try to translate div content after ajax has loaded it, it fails because of the whitespace issue.
I really don't have a preference of jQuery or Pure Javascript, I just want a working solution.
Thank you all for being patient. I personally thought I was extremely clear in my description, I apologize if it wasn't. I wasn't trying to be obscure or make it difficult to get help. But please don't insult me, by implying I am trying to make it unclear.
Thanks.
Hm... You have jQuery but don't use it?
$(divid).children(".yourSpecialClassName").each( function() {
doSomethingWith(this);
});
To get the CSS class attribute value, this will do:
$(divid).children().each( function() {
alert(this.className);
});
Based on the function you posted now, you want this:
$(divid).find(".status_bar").each( function() {
$(this).text( function(i, text) {
var x = $.inArray(en_lang, $.trim(text));
if (x > -1) {
console.log('Current Value ['+text+'] English ['+en_lang[x]+'] Translation ['+other_lang[x]+']');
return other_lang[x];
}
return text;
});
});
And please, don't ever use "do magic" as a comment again. This is incredibly lame.
EDIT. This can be made much more efficient (superfluous console.log() removed):
$(divid).find(".status_bar").each( function() {
// prepare dictionary en_lang => other_lang
var dict = {};
$.each(en_lang, function(x, word) { dict[word] = other_lang[x]; });
$(this).text( function(i, text) {
var t = $.trim(text);
return (t in dict) ? dict[t] : text;
});
});
if you are using jquery you can do this:
$("#myDiv").find("*").each(
function(){
var myclass = $(this).attr("class");
}
);
Your sample code doesn't make sense.
$(this).attr('value', to);
'value' is an attribute of the tag, not the text content.
Did you really mean to do this instead?
$(this).text(to);
Also, you've re-edited your question, but you're still trying to loop through the child nodes using non-jQuery methods. You said "The last obstacle I had in my script, of which you see a small portion of, is getting the classname. I need the class name so that I can filter down what content get's text replaced."
If you are using jQuery it is completely unnecessary to loop through anything to get a class name. You simply have to use a proper selector in the first place.
$(divid).find(".status_bar.replaceme").each( function() {
// .replaceme is whatever class you're using for the stuff you want to change
// .status_bar.replaceme matches all elements with BOTH status_bar and replaceme classes
var value = $.trim($(this).text());
// if value is not defined thru browser bugs do not replace
if (typeof(value) != 'undefined') {
// it is a text node. do magic.
// NOTE: The following is inefficient but I won't fix it.
// You're better off using an associative array
for (var x = en_count; x > 0; x--) {
// get current english phrase
var from = en_lang[x];
// get current other language phrase
var to = other_lang[x];
if (value == from) {
console.log('Current Value ['+value+'] English ['+from+'] Translation ['+to+']');
// value = to; <-- useless, get rid of it.
$(this).text(to);
// or $(this).html(to);
}
}
}
});

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