I'm working on a Chrome extension that allows a user to highlight text on a webpage. Simple, but it's to help me learn. Right now, I'm stuck and looking for how to best solve a problem.
Currently, I can highlight selected text that persists on the page.
JavaScript
function addHilite(color) {
var range, sel = window.getSelection();
if (sel.rangeCount && sel.getRangeAt) {
range = sel.getRangeAt(0);
}
document.designMode = "on";
if (range) {
sel.addRange(range);
};
if (!document.execCommand("hiliteColor", false, "#FFFF00")) {
document.execCommand("backColor", false, "#FFFF00");
}
document.designMode = "off";
console.log(range);
}
I'm trying to get to a point where the user could select a highlighted range and use the same browser action to undo a highlight. I thought localStorage would be a good way to save the state between each click, but I can't figure out how to store multiple ranges as a string for reference. Is there a better way to do this?
localStorage Experiment
function sel() {
var getText = window.getSelection().toString();
localStorage.setItem('getText', JSON.stringify(getText));
console.log(JSON.parse(localStorage.getItem('getText')));
}
do you mean something like this?
var selections = [];
function sel() {
var getText = window.getSelection().toString();
selections.push(getText);
localStorage.setItem('getText', selections);
console.log(localStorage.getItem('getText'));
}
Related
My current solution is:
Get selected html (include text and html tag), namely: selText
highlightText = <span>selText</span>
Find selText in innerHTML of the body or document (or the element which the mouse dragged in)
Replace with highlightText
But if the document is: a a a a a a and user selects the last a. My function will highlight the first or all a.
Any suggestion?
Thank you.
i think your question is duplicated, anyway i just searched the internet and found this article.
Below the final code to achieve what you ask
function highlightSelection() {
var selection;
//Get the selected stuff
if(window.getSelection)
selection = window.getSelection();
else if(typeof document.selection!="undefined")
selection = document.selection;
//Get a the selected content, in a range object
var range = selection.getRangeAt(0);
//If the range spans some text, and inside a tag, set its css class.
if(range && !selection.isCollapsed)
{
if(selection.anchorNode.parentNode == selection.focusNode.parentNode)
{
var span = document.createElement('span');
span.className = 'highlight-green';
range.surroundContents(span);
}
}
}
I also found this library rangy that is an helper you can use to select text but only works with jquery so i prefer the first vanilla-js solution.
var el = $("<span></span>");
el.text(rangy.getSelection().getRangeAt(0).toString());
rangy.getSelection().getRangeAt(0).deleteContents();
rangy.getSelection().getRangeAt(0).insertNode(el.get(0));
rangy.getSelection().getRangeAt(0).getSelection().setSingleRange(range);
On Range and User Selection
You have to select range using Document.createRange that return a Range object before you can use Range.surroundContents(), you could create a range this way.
var range = document.createRange();
range.setStart(startNode, startOffset);
range.setEnd(endNode, endOffset);
In practice you follow this guide to understand range and selection tecniques.
The most important point is contained in this code
var userSelection;
if (window.getSelection) {
userSelection = window.getSelection();
}
else if (document.selection) { // should come last; Opera!
userSelection = document.selection.createRange();
}
After this you can use
userSelection.surroundContents()
I'm trying to make a JavaScript bookmarklet that will act as a highlighter, changing the background of selected text on a webpage to yellow when the bookmarklet is pressed.
I'm using the following code to get the selected text, and it works fine, returning the correct string
function getSelText() {
var SelText = '';
if (window.getSelection) {
SelText = window.getSelection();
} else if (document.getSelection) {
SelText = document.getSelection();
} else if (document.selection) {
SelText = document.selection.createRange().text;
}
return SelText;
}
However, when I created a similar function to change the CSS of the selected text using jQuery, it isn't working:
function highlightSelText() {
var SelText;
if (window.getSelection) {
SelText = window.getSelection();
} else if (document.getSelection) {
SelText = document.getSelection();
} else if (document.selection) {
SelText = document.selection.createRange().text;
}
$(SelText).css({'background-color' : 'yellow', 'font-weight' : 'bolder'});
}
Any ideas?
The easiest way to do this is to use execCommand(), which has a command to change the background colour in all modern browsers.
The following should do what you want on any selection, including ones spanning multiple elements. In non-IE browsers it turns on designMode, applies a background colour and then switches designMode off again.
UPDATE
Fixed in IE 9.
function makeEditableAndHighlight(colour) {
var range, sel = window.getSelection();
if (sel.rangeCount && sel.getRangeAt) {
range = sel.getRangeAt(0);
}
document.designMode = "on";
if (range) {
sel.removeAllRanges();
sel.addRange(range);
}
// Use HiliteColor since some browsers apply BackColor to the whole block
if (!document.execCommand("HiliteColor", false, colour)) {
document.execCommand("BackColor", false, colour);
}
document.designMode = "off";
}
function highlight(colour) {
var range, sel;
if (window.getSelection) {
// IE9 and non-IE
try {
if (!document.execCommand("BackColor", false, colour)) {
makeEditableAndHighlight(colour);
}
} catch (ex) {
makeEditableAndHighlight(colour)
}
} else if (document.selection && document.selection.createRange) {
// IE <= 8 case
range = document.selection.createRange();
range.execCommand("BackColor", false, colour);
}
}
Here is a crude example of how it could work. As Zack points out you'll need to be aware of cases where the selection spans multiple elements. This isn't intended to be used as-is, just something to help get ideas flowing. Tested in Chrome.
var selection = window.getSelection();
var text = selection.toString();
var parent = $(selection.focusNode.parentElement);
var oldHtml = parent.html();
var newHtml = oldHtml.replace(text, "<span class='highlight'>"+text+"</span>");
parent.html( newHtml );
To make the highlight stick permanently, I believe you are going to have to wrap the selection in a new DOM element (span should do), to which you can then attach style properties. I don't know if jQuery can do that for you. Keep in mind that selections can span element boundaries, so in the general case you're going to have to inject a whole bunch of new elements
Have a look at a little example i made at http://www.jsfiddle.net/hbwEE/3/
It does not take into account selections that span multiple elements..
(IE will do but will mess the html a bit ..)
In Firefox, you can use the ::-moz-selection psuedo-class.
In Webkit, you can use the ::selection pseudo-class.
I like Tim's answer, it's clean and fast. But it also shuts down the doors to doing any interactions with the highlights.
Inserting inline elements directly around the texts is a bad choice, as they broke the text flow and mess things up in complex situations,
So I suggest a dirty hack that
calculates the absolute layout of each line of selected text (no matter where they are),
then insert colored, semi-transparent inline-block elements in the end of the document body.
This chrome extension is an example of how this can be done.
It uses API from this library to get the absolute layout of each selected line.
I'm trying to save information about text that a user has highlighted in a webpage. Currently I'm using the getSelection method shown below:
var txt = '';
if (window.getSelection){txt = window.getSelection();}
else if (document.getSelection){txt = document.getSelection();}
else if (document.selection){txt = document.selection.createRange().text;}
else return;
to retrieve the highlighted text. Then I'm searching through the entire text body and storing the indices of the highlighted text. The getSelection method only returns what text is highlighted so the problem is that if the highlighted text appears multiple times in the text body, the search could find the wrong repeat of the text and thus save the wrong indices.
Any ideas how to ensure that I'm saving the right indices?
Thanks!
QuirksMode has an article about this.
You'd probably be interested in this code:
var userSelection;
if (window.getSelection) {
userSelection = window.getSelection();
}
else if (document.selection) { // should come last; Opera!
userSelection = document.selection.createRange();
}
var rangeObject = getRangeObject(userSelection);
function getRangeObject(selectionObject) {
if (selectionObject.getRangeAt)
return selectionObject.getRangeAt(0);
else { // Safari!
var range = document.createRange();
range.setStart(selectionObject.anchorNode,selectionObject.anchorOffset);
range.setEnd(selectionObject.focusNode,selectionObject.focusOffset);
return range;
}
}
I am writing a script on which the user needs to be able to select some text which is sent via ajax to the backend script for further process.
I can select plain text nodes fine or text nodes that have bold, italic or underlined text inside it.
For e.g
<p>This is <strong>some</strong> cool <em>italic</em> text, <u>really!</u></p>
So, that works, that is cool.
However, the issue is, if the text node starts with hsome bold, italic or underlined text OR even headings it outputs the following error on firefox console:
The boundary-points of a range does not meet specific requirements." code: "1 range.surroundContents($('<span...wAnno_'+newLen+'"></span>').get(0));
The error is output when the user selects something like:
<strong>Mark says</strong> Hi
OR
<em>Mark says</em> Hi
OR
<u>Mark says</u> Hi
The same error outputs even if a text is enclosed inside heading tags e.g <h2>test</h2>
My code looks like:
var select = window.getSelection();
var parents = $(select.focusNode).parents('.the-content');
if($(select.focusNode).parent().hasClass('.highlighted')) {
alert('This text is already highlighted');
} else {
for(var i = 0; i < select.rangeCount; i++) {
var range = select.getRangeAt(i);
range.surroundContents($('<span class="newHighlight" id="newHigh_'+newLen+'"></span>').get(0));
}
}
var selectedText = select.toString();
I need help with fixing this.
Help with the code will be awesome.
The problem is that the surroundContents method of Range can't work on a Range where the start and end boundaries lie within different elements, because surrounding the contents of such a Range within an element would not produce valid HTML. If changing the background colour of your Range is all you need to do, you could use the following trick with document.execCommand:
function highlight(colour) {
var range, sel;
if (window.getSelection) {
// Non-IE case
sel = window.getSelection();
if (sel.getRangeAt) {
range = sel.getRangeAt(0);
}
document.designMode = "on";
if (range) {
sel.removeAllRanges();
sel.addRange(range);
}
// Use HiliteColor since some browsers apply BackColor to the whole block
if ( !document.execCommand("HiliteColor", false, colour) ) {
document.execCommand("BackColor", false, colour);
}
document.designMode = "off";
} else if (document.selection && document.selection.createRange) {
// IE case
range = document.selection.createRange();
range.execCommand("BackColor", false, colour);
}
}
Otherwise, you'll need to walk through the text nodes within the range and surround each with a <span>, which is not trivial. I've been working on a cross-browser range and selection library that includes a module for applying a CSS class to the contents of a selection or Range at http://code.google.com/p/rangy/, although that module is a few days away from being documented and released.
I select some text on the html page(opened in firefox) using mouse,and using javascript functions, i create/get the rangeobject corresponding to the selected text.
userSelection =window.getSelection();
var rangeObject = getRangeObject(userSelection);
Now i want to highlight all the text which comes under the rangeobject.I am doing it like this,
var span = document.createElement("span");
rangeObject.surroundContents(span);
span.style.backgroundColor = "yellow";
Well,this works fine, only when the rangeobject(startpoint and endpoint) lies in the same textnode,then it highlights the corresponding text.Ex
<p>In this case,the text selected will be highlighted properly,
because the selected text lies under a single textnode</p>
But if the rangeobject covers more than one textnode, then it is not working properlay, It highlights only the texts which lie in the first textnode,Ex
<p><h3>In this case</h3>, only the text inside the header(h3)
will be highlighted, not any text outside the header</p>
Any idea how can i make, all the texts which comes under rangeobject,highlighted,independent of whether range lies in a single node or multiple node?
Thanks....
I would suggest using document's or the TextRange's execCommand method, which is built for just such a purpose, but is usually used in editable documents. Here's the answer I gave to a similar question:
The following should do what you want. In non-IE browsers it turns on designMode, applies a background colour and then switches designMode off again.
UPDATE
Fixed to work in IE 9.
UPDATE 12 September 2013
Here's a link detailing a method for removing highlights created by this method:
https://stackoverflow.com/a/8106283/96100
function makeEditableAndHighlight(colour) {
var range, sel = window.getSelection();
if (sel.rangeCount && sel.getRangeAt) {
range = sel.getRangeAt(0);
}
document.designMode = "on";
if (range) {
sel.removeAllRanges();
sel.addRange(range);
}
// Use HiliteColor since some browsers apply BackColor to the whole block
if (!document.execCommand("HiliteColor", false, colour)) {
document.execCommand("BackColor", false, colour);
}
document.designMode = "off";
}
function highlight(colour) {
var range;
if (window.getSelection) {
// IE9 and non-IE
try {
if (!document.execCommand("BackColor", false, colour)) {
makeEditableAndHighlight(colour);
}
} catch (ex) {
makeEditableAndHighlight(colour)
}
} else if (document.selection && document.selection.createRange) {
// IE <= 8 case
range = document.selection.createRange();
range.execCommand("BackColor", false, colour);
}
}
Rangy is a cross-browser range and selection library that solves this problem perfectly with its CSS Class Applier module. I'm using it to implement highlighting across a range of desktop browsers and on iPad and it works perfectly.
Tim Down's answer is great but Rangy spares you from having to write and maintain all that feature detection code yourself.
var userSelection = document.getSelection();
var range = userSelection.getRangeAt(0);
Instead of surroundContent method you can use the appendChild and extractContents methods this way:
let newNode = document.createElement('mark');
newNode.appendChild(range.extractContents());
range.insertNode(newNode);
function markNode() {
if(document.getSelection() && document.getSelection().toString().length){
let range = document.getSelection().getRangeAt(0);
let newNode = document.createElement('mark');
newNode.appendChild(range.extractContents());
range.insertNode(newNode);
}
else{
alert('please make selection of text to mark');
}
}
function resetContent() {
testMe.innerHTML = `Remember: Read and <strong>stay strong</strong>`;
}
<p id="testMe">Remember: Read and <strong>stay strong</strong></p>
<div><button onclick="markNode()">markNode</button></div>
<div><button onclick="resetContent()">resetContent</button></div>
Could you please elaborate the need of this functionality. If you only want to change the highlight style of the selected text you can use CSS: '::selection'
More Info:
http://www.quirksmode.org/css/selection.html
https://developer.mozilla.org/en/CSS/::selection
Can you try adding a class for the surrounding span and apply hierarchical CSS?
var span = document.createElement("span");
span.className="selection";
rangeObject.surroundContents(span);
In CSS definition,
span.selection, span.selection * {
background-color : yellow;
}
I did not try it. But just guessing that it would work.