I am looking for a way to find instances of a certain character within a certain element. I am aware of doing something like:
var string = 'this is a string';
string.indexOf('a');
however, i want indexOf to look at a particular tag within a particular html file. (in this case, p tags). I have commented out what i tried to use in order to achieve this.
function findQuestion() {
// var string1 = document.getElementsByTagName('p');
var string2 = '??';
if (string2.indexOf('?') !== -1) {
console.log('foundQuestion');
}
else {
console.log('nothing');
}
}
findQuestion();
This code obviously just checks to see that there is a '?' in string2, but how do i write this to find all instances of '?' within p tags and return all content preceding that up to the opening p tag in which the '?' was found?
thanks.
How you could do that:
Get all p elements.
Create an empty array, results
Iterate over them and check for each p element
If the p's innerHTML contains a question mark split the string at the question mark, get the first part and add a question mark. Then add this new string to the results array
Return the results array
Example Code:
function findQuestion() {
var ps = document.getElementsByTagName('p');
var result = [];
for(var i = 0; i < ps.length; i++){
var p = ps[i];
if (p.innerHTML.indexOf('?') !== -1) {
result.push(p.innerHTML.split("?")[0] + "?");
}
}
return result;
}
findQuestion();
http://jsfiddle.net/3o4tcchL/1/
Use a loop condition to check the entirety of the content within , after that use something like slice, which will grab everything up to a particular index you specify.
I'm wondering if there is a lightweight way I could use JavaScript or jQuery to sniff out a specific text character across a document; say € and find all instances of this character. And then! Write an ability to replace all instances of this with say a $.
I found this snippet for starters:
var str = 'test: '';
str = str.replace(/'/g, "'");
Essentially; I am wanting a solution for a one page document. Grab all instances of X and make it XY. Only text characters.
How about this, replacing # with $:
$("body").children().each(function () {
$(this).html( $(this).html().replace(/#/g,"$") );
});
http://jsfiddle.net/maximua/jp96C/1/
ECMAScript 2015+ approach
Pitfalls when solving this task
This seems like an easy task, but you have to take care of several things:
Simply replacing the entire HTML (e.g. using innerHTML) causes the affected subtree of the DOM to be entirely deleted and replaced, however event listeners are attached to the existing, now deleted elements, so they’re deleted with them. Similarly, WeakMap entries for the existing elements will all be deleted. This is because all of these things need the exact references to the elements or nodes; a replaced innerHTML will create entirely new references and discard the old ones.
Replacing the HTML may also replace <script> or <style> contents, or HTML tag or attribute names, which is not always desired.
Changing the HTML may result in an xss attack.
You may want to replace attribute values, e.g. for title and alt, in a controlled manner as well, but those all-or-nothing approaches as well as regexes are ill-equipped to do so.
Guarding against xss attacks generally can’t be solved by using the approaches below. E.g. if a fetch call reads a URL from somewhere on the page, then sends a request to that URL, the functions below won’t stop that, since this scenario is inherently unsafe.
Replacing the text contents of all elements
This basically selects all elements that contain normal text, goes through their child nodes — among those are also text nodes —, seeks those text nodes out and replaces their contents.
You can optionally specify a different root target, e.g. replaceOnDocument(/€/g, "$", { target: someElement });; by default, the <body> is chosen.
const replaceOnDocument = (pattern, string, {target = document.body} = {}) => {
// Handle `string` — see the last section
[
target,
...target.querySelectorAll("*:not(script):not(noscript):not(style)")
].forEach(({childNodes: [...nodes]}) => nodes
.filter(({nodeType}) => nodeType === Node.TEXT_NODE)
.forEach((textNode) => textNode.textContent = textNode.textContent.replace(pattern, string)));
};
replaceOnDocument(/€/g, "$");
Replacing text nodes, element attributes and properties
Now, this is a little more complex: you need to check three cases: whether a node is a text node, whether it’s an element and its attribute should be replaced, or whether it’s an element and its property should be replaced. A replacer object provides methods for text nodes and for elements.
Before replacing attributes and properties, the replacer needs to check whether the element has a matching attribute; otherwise new attributes get created, undesirably. It also needs to check whether the targeted property is a string, since only strings can be replaced, or whether the matching property to the targeted attribute is not a function, since this may lead to an xss attack.
In the example below, you can see how to use the extended features: in the optional third argument, you may add an attrs property and a props property, which is an iterable (e.g. an array) each, for the attributes to be replaced and the properties to be replaced, respectively.
You’ll also notice that this snippet uses flatMap. If that’s not supported, use a polyfill or replace it by the reduce–concat, or map–reduce–concat construct, as seen in the linked documentation.
const replaceOnDocument = (() => {
const replacer = {
[Node.TEXT_NODE](node, pattern, string){
node.textContent = node.textContent.replace(pattern, string);
},
[Node.ELEMENT_NODE](node, pattern, string, {attrs, props} = {}){
attrs.forEach((attr) => {
if(typeof node[attr] !== "function" && node.hasAttribute(attr)){
node.setAttribute(attr, node.getAttribute(attr).replace(pattern, string));
}
});
props.forEach((prop) => {
if(typeof node[prop] === "string" && node.hasAttribute(prop)){
node[prop] = node[prop].replace(pattern, string);
}
});
}
};
return (pattern, string, {target = document.body, attrs: [...attrs] = [], props: [...props] = []} = {}) => {
// Handle `string` — see the last section
[
target,
...[
target,
...target.querySelectorAll("*:not(script):not(noscript):not(style)")
].flatMap(({childNodes: [...nodes]}) => nodes)
].filter(({nodeType}) => replacer.hasOwnProperty(nodeType))
.forEach((node) => replacer[node.nodeType](node, pattern, string, {
attrs,
props
}));
};
})();
replaceOnDocument(/€/g, "$", {
attrs: [
"title",
"alt",
"onerror" // This will be ignored
],
props: [
"value" // Changing an `<input>`’s `value` attribute won’t change its current value, so the property needs to be accessed here
]
});
Replacing with HTML entities
If you need to make it work with HTML entities like , the above approaches will just literally produce the string , since that’s an HTML entity and will only work when assigning .innerHTML or using related methods.
So let’s solve it by passing the input string to something that accepts an HTML string: a new, temporary HTMLDocument. This is created by the DOMParser’s parseFromString method; in the end we read its documentElement’s textContent:
string = new DOMParser().parseFromString(string, "text/html").documentElement.textContent;
If you want to use this, choose one of the approaches above, depending on whether or not you want to replace HTML attributes and DOM properties in addition to text; then simply replace the comment // Handle `string` — see the last section by the above line.
Now you can use replaceOnDocument(/Güterzug/g, "Güterzug");.
NB: If you don’t use the string handling code, you may also remove the { } around the arrow function body.
Note that this parses HTML entities but still disallows inserting actual HTML tags, since we’re reading only the textContent. This is also safe against most cases of xss: since we’re using parseFromString and the page’s document isn’t affected, no <script> gets downloaded and no onerror handler gets executed.
You should also consider using \xAD instead of directly in your JavaScript string, if it turns out to be simpler.
My own suggestion is as follows:
function nativeSelector() {
var elements = document.querySelectorAll("body, body *");
var results = [];
var child;
for(var i = 0; i < elements.length; i++) {
child = elements[i].childNodes[0];
if(elements[i].hasChildNodes() && child.nodeType == 3) {
results.push(child);
}
}
return results;
}
var textnodes = nativeSelector(),
_nv;
for (var i = 0, len = textnodes.length; i<len; i++){
_nv = textnodes[i].nodeValue;
textnodes[i].nodeValue = _nv.replace(/£/g,'€');
}
JS Fiddle demo.
The nativeSelector() function comes from an answer (posted by Anurag) to this question: getElementsByTagName() equivalent for textNodes.
I think you may be overthinking this.
My approach is simple.
Enclose you page with a div tag:
<div id="mydiv">
<!-- you page here -->
</div>
In your javascript:
var html=document.getElementById('mydiv').innerHTML;
html = html.replace(/this/g,"that");
document.getElementById('mydiv').innerHTML=html;
Similar to #max-malik's answer, but without using jQuery, you can also do this using document.createTreeWalker:
button.addEventListener('click', e => {
const treeWalker = document.createTreeWalker(document.body, NodeFilter.SHOW_TEXT);
while (treeWalker.nextNode()) {
const node = treeWalker.currentNode;
node.textContent = node.textContent.replace(/#/g, '$');
}
})
<div>This is an # that we are # replacing.</div>
<div>This is another # that we are replacing.</div>
<div>
<span>This is an # in a span in # div.</span>
</div>
<br>
<input id="button" type="button" value="Replace # with $" />
Vanilla JavaScript solution:
document.body.innerHTML = document.body.innerHTML.replace(/Original/g, "New")
The best would be to do this server-side or wrap the currency symbols in an element you can select before returning it to the browser, however if neither is an option, you can select all text nodes within the body and do the replace on them. Below i'm doing this using a plugin i wrote 2 years ago that was meant for highlighting text. What i'm doing is finding all occurrences of € and wrapping it in a span with the class currency-symbol, then i'm replacing the text of those spans.
Demo
(function($){
$.fn.highlightText = function () {
// handler first parameter
// is the first parameter a regexp?
var re,
hClass,
reStr,
argType = $.type(arguments[0]),
defaultTagName = $.fn.highlightText.defaultTagName;
if ( argType === "regexp" ) {
// first argument is a regular expression
re = arguments[0];
}
// is the first parameter an array?
else if ( argType === "array" ) {
// first argument is an array, generate
// regular expression string for later use
reStr = arguments[0].join("|");
}
// is the first parameter a string?
else if ( argType === "string" ) {
// store string in regular expression string
// for later use
reStr = arguments[0];
}
// else, return out and do nothing because this
// argument is required.
else {
return;
}
// the second parameter is optional, however,
// it must be a string or boolean value. If it is
// a string, it will be used as the highlight class.
// If it is a boolean value and equal to true, it
// will be used as the third parameter and the highlight
// class will default to "highlight". If it is undefined,
// the highlight class will default to "highlight" and
// the third parameter will default to false, allowing
// the plugin to match partial matches.
// ** The exception is if the first parameter is a regular
// expression, the third parameter will be ignored.
argType = $.type(arguments[1]);
if ( argType === "string" ) {
hClass = arguments[1];
}
else if ( argType === "boolean" ) {
hClass = "highlight";
if ( reStr ) {
reStr = "\\b" + reStr + "\\b";
}
}
else {
hClass = "highlight";
}
if ( arguments[2] && reStr ) {
reStr = reStr = "\\b" + reStr + "\\b";
}
// if re is not defined ( which means either an array or
// string was passed as the first parameter ) create the
// regular expression.
if (!re) {
re = new RegExp( "(" + reStr + ")", "ig" );
}
// iterate through each matched element
return this.each( function() {
// select all contents of this element
$( this ).find( "*" ).andSelf().contents()
// filter to only text nodes that aren't already highlighted
.filter( function () {
return this.nodeType === 3 && $( this ).closest( "." + hClass ).length === 0;
})
// loop through each text node
.each( function () {
var output;
output = this.nodeValue
.replace( re, "<" + defaultTagName + " class='" + hClass + "'>$1</" + defaultTagName +">" );
if ( output !== this.nodeValue ) {
$( this ).wrap( "<p></p>" ).parent()
.html( output ).contents().unwrap();
}
});
});
};
$.fn.highlightText.defaultTagName = "span";
})( jQuery );
$("body").highlightText("€","currency-symbol");
$("span.currency-symbol").text("$");
Use split and join method
$("#idBut").click(function() {
$("body").children().each(function() {
$(this).html($(this).html().split('#').join("$"));
});
});
here is solution
In javascript without using jquery:
document.body.innerText = document.body.innerText.replace('actualword', 'replacementword');
You can use:
str.replace(/text/g, "replaced text");
For each element inside document body modify their text using .text(fn) function.
$("body *").text(function() {
return $(this).text().replace("x", "xy");
});
As you'll be using jQuery anyway, try:
https://github.com/cowboy/jquery-replacetext
Then just do
$("p").replaceText("£", "$")
It seems to do good job of only replacing text and not messing with other elements
str.replace(/replacetext/g,'actualtext')
This replaces all instances of replacetext with actualtext
Here is something that might help someone looking for this answer:
The following uses jquery it searches the whole document and only replaces the text.
for example if we had
overpopulation
and we wanted to add a span with the class overpop around the word overpopulation
<span class="overpop">overpopulation</span>
we would run the following
$("*:containsIN('overpopulation')").filter(
function() {
return $(this).find("*:contains('" + str + "')").length == 0
}
).html(function(_, html) {
if (html != 'undefined') {
return html.replace(/(overpopulation)/gi, '<span class="overpop">$1</span>');
}
});
the search is case insensitive searches the whole document and only replaces the text portions in this case we are searching for the string 'overpopulation'
$.extend($.expr[":"], {
"containsIN": function(elem, i, match, array) {
return (elem.textContent || elem.innerText || "").toLowerCase().indexOf((match[3] || "").toLowerCase()) >= 0;
}
});
I'm trying to write a jQuery or pure Javascript function (preferring the more readable solution) that can count the length of a starting tag or ending tag in an HTML document.
For example,
<p>Hello.</p>
would return 3 and 4 for the starting and ending tag lengths. Adding attributes,
<span class="red">Warning!</span>
would return 18 and 7 for the starting and ending tag lengths. Finally,
<img src="foobar.png"/>
would return 23 and 0 (or -1) for the starting and ending tag lengths.
I'm looking for a canonical, guaranteed-to-work-according-to-spec solution, so I'm trying to use DOM methods rather than manual text manipulations. For example, I would like the solution to work even for weird cases like
<p>spaces infiltrating the ending tag</ p >
and
<img alt="unended singleton tags" src="foobar.png">
and such. That is, my hope is that as long as we use proper DOM methods, we should be able to find the number of characters between < and > no matter how weird things get, even
<div data-tag="<div>">HTML-like strings within attributes</div>
I have looked at the jQuery API (especially the Manipulation section, including DOM Insertion and General Attributes subsections), but I don't see anything that would help.
Currently the best idea I have, given an element node is
lengthOfEndTag = node.tagName.length + 3;
lengthOfStartTag = node.outerHTML.length
- node.innerHTML.length
- lengthOfEndTag;
but of course I don't want to make such an assumption for the end tag.
(Finally, I'm familiar with regular expressions—but trying to avoid them if at all possible.)
EDIT
#Pointy and #squint helped me understand that it's not possible to see </ p >, for example, because the HTML is discarded once the DOM is created. That's fine. The objective, adjusted, is to find the length of the start and end tags as would be rendered in outerHTML.
An alternate way to do this could be to use XMLSerializer's serializeToString on a clone copy of the node (with id set) to avoid having to parse innerHTML, then split over "><"
var tags = (function () {
var x = new XMLSerializer(); // scope this so it doesn't need to be remade
return function tags(elm) {
var s, a, id, n, o = {open: null, close: null}; // spell stuff with var
if (elm.nodeType !== 1) throw new TypeError('Expected HTMLElement');
n = elm.cloneNode(); // clone to get rid of innerHTML
id = elm.getAttribute('id'); // re-apply id for clone
if (id !== null) n.setAttribute('id', id); // if it was set
s = x.serializeToString(n); // serialise
a = s.split('><');
if (a.length > 1) { // has close tag
o.close = '<' + a.pop();
o.open = a.join('><') + '>'; // join "just in case"
}
else o.open = a[0]; // no close tag
return o;
}
}()); // self invoke to init
After running this, you can access .length of open and close properties
tags(document.body); // {open: "<body class="question-page">", close: "</body>"}
What if an attribute's value has >< in it? XMLSerializer escapes this to >< so it won't change the .split.
What about no close tag? close will be null.
This answer helped me understand what #Pointy and #squint were trying to say.
The following solution works for me:
$.fn.lengthOfStartTag = function () {
var node = this[0];
if (!node || node.nodeType != 1) {
$.error("Called $.fn.lengthOfStartTag on non-element node.");
}
if (!$(node).is(":empty")) {
return node.outerHTML.indexOf(node.innerHTML);
}
return node.outerHTML.length;
}
$.fn.lengthOfEndTag = function () {
var node = this[0];
if (!node || node.nodeType != 1) {
$.error("Called $.fn.lengthOfEndTag on non-element node.");
}
if (!$(node).is(":empty")) {
var indexOfInnerHTML = node.outerHTML.indexOf(node.innerHTML);
return node.outerHTML.length - (indexOfInnerHTML + node.innerHTML.length);
}
return -1;
}
Sample jsFiddle here.
I am currently learning jQuery. I know that jQuery is a custom library for JavaScript.
I am doing some learning examples in a book that is only using JavaScript, and to further my learning experience, I am trying to make use of jQuery for anything that might be more efficient.
So, I have this code:
function addLetter(foo) {
$(foo).unbind('click');
var tileLetter = $(foo).attr('class').split(' ');
var letter = tileLetter[2].charAt(1);
if (document.getElementById('currentWord').childNodes.length > 0) {
$('#currentWord p').append(letter);
} else {
var p = document.createElement('p');
var txt = document.createTextNode(letter);
p.appendChild(txt);
$('#currentWord').append(p);
}
}
Question #1:
If I change document.getElementById('currentWord').childNodes.length to $('#currentWord').childNodes.length it doesn't work. I thought the jQuery selector was the same thing as the JS document.getElementById as that it brought me back the DOM element. If that was the case, it'd make sense to be able to use the .childNodes.length functions on it; but it doesn't work. I guess it's not the same thing?
Question #2:
The code is textbook code. I have added all the jQuery that there is in it. My jQuery knowlede is limited, is there a more efficient way to execute the function?
The function's purpose:
This function is supposed to create a p element and fill it with a Text Node if it's the first time it's run. If the p element has already been created, it simply appends characters into it.
This is a word generating game, so you click on a letter and it gets added to a 'currentWord' div. The tile's letter is embedded in the 3rd css class, hence the attr splitting.
Thanks!
document.getElementById('currentWord')
returns a DOM object whereas $('#currentWord') returns a DOM object wrapped inside a jQuery object.
To get the plain DOM object you can do
$('#currentWord').get(0)
So
$('#currentWord').get(0).childNodes.length
should work.
Question #1:
jQuery returns a jQuery object. To return it to a regular javascript object use $(object)[0] and you can then treat it as a plain javascript (or DOM) object.
Question #2:
The efficiency looks good to me. Although you might want to use spans instead of p elements.
I guess one thing you could do (even though yours looks to run very fast) is cache the dom element:
function addLetter(foo) {
$(foo).unbind('click');
var tileLetter = $(foo).attr('class').split(' ');
var letter = tileLetter[2].charAt(1);
var currentWord = document.getElementById('currentWord');
if (currentWord.childNodes.length > 0) {
$(currentWord).find('p').append(letter);
} else {
var p = document.createElement('p');
p.innerHTML = letter;
currentWord.appendChild(p);
}
}
Calls to the jQuery() function ($()) return a jQuery object containing the matching elements, not the elements themselves.
Calling $('#some-id') will, then, return a jQuery object that contains the element that would be selected by doing document.getElementById('some-id'). In order to access that element directly, you can get it out of that jQuery object, using either the .get() function or an array index syntax: $('#some-id')[0] (it's 0-indexed).
I think you can replace all of this with a call to the text function.
function addLetter(foo) {
$(foo).unbind('click');
var tileLetter = $(foo).attr('class').split(' ');
var letter = tileLetter[2].charAt(1);
var currentWordP = $('#currentWord p');
if (currentWordP.size() > 0) {
currentWordP.text(currentWordP.text() + letter);
} else {
$('#currentWord').append("<p>" + letter + "</p>");
}
}
1: Use $.get(0) or $[0] to get the DOM element. e.x. $('#currentWord')[0].childNodes.length.
2: Try this:
function addLetter(foo) {
$(foo).unbind('click');
var tileLetter = $(foo).attr('class').split(' ');
var letter = tileLetter[2].charAt(1);
if ($('#currentWord p').length > 0) {
$('#currentWord p').append(letter);
} else {
$('#currentWord').append(
$('<p />', { text: letter })
);
}
}
Question #1:
document.getElementById returns DOM object. more
childNodes.length is property of Node object which is returned by document.getElementById.
jQuery selector returns jQuery object more. You can get DOM object from jQuery object using .get
$('#IDselector').get(0) = document.getElementById('IDselector')
Question #2:
function addLetter(foo) {
$(foo).unbind('click');
var tileLetter = $(foo).attr('class').split(' ');
var letter = tileLetter[2].charAt(1);
if ($('currentWord p').length > 0) {
$('#currentWord p').append(letter);
} else {
var p = $('<p />').text(letter);
$('#currentWord').append(p);
}
}
imagine this html on a page
<div id="hpl_content_wrap">
<p class="foobar">this is one word and then another word comes in foobar and then more words and then foobar again.</p>
<p>this is a link with foobar in an attribute but only the foobar inside of the link should be replaced.</p>
</div>
using javascript, how to change all 'foobar' words to 'herpderp' without changing any inside of html tags?
ie. only plain text should be changed.
so the successful html changed will be
<div id="hpl_content_wrap">
<p class="foobar">this is one word and then another word comes in herpderp and then more words and then herpderp again.</p>
<p>this is a link with herpderp in an attribute but only the herpderp inside of the link should be replaced. </p>
</div>
Here is what you need to do...
Get a reference to a bunch of elements.
Recursively walk the children, replacing text in text nodes only.
Sorry for the delay, I was sidetracked before I could add the code.
var replaceText = function me(parentNode, find, replace) {
var children = parentNode.childNodes;
for (var i = 0, length = children.length; i < length; i++) {
if (children[i].nodeType == 1) {
me(children[i], find, replace);
} else if (children[i].nodeType == 3) {
children[i].data = children[i].data.replace(find, replace);
}
}
return parentNode;
}
replaceText(document.body, /foobar/g, "herpderp");
jsFiddle.
It's a simple matter of:
identifying all text nodes in the DOM tree,
then replacing all foobar strings in them.
Here's the full code:
// from: https://stackoverflow.com/questions/298750/how-do-i-select-text-nodes-with-jquery
var getTextNodesIn = function (el) {
return $(el).find(":not(iframe)").andSelf().contents().filter(function() {
return this.nodeType == 3;
});
};
var replaceAllText = function (pattern, replacement, root) {
var nodes = getTextNodesIn(root || $('body'))
var re = new RegExp(pattern, 'g')
nodes.each(function (i, e) {
if (e.textContent && e.textContent.indexOf(pattern) != -1) {
e.textContent = e.textContent.replace(re, replacement);
}
});
};
// replace all text nodes in document's body
replaceAllText('foobar', 'herpderp');
// replace all text nodes under element with ID 'someRootElement'
replaceAllText('foobar', 'herpderp', $('#someRootElement'));
Note that I do a precheck on foobar to avoid processing crazy long strings with a regexp. May or may not be a good idea.
If you do not want to use jQuery, but only pure JavaScript, follow the link in the code snippet ( How do I select text nodes with jQuery? ) where you'll also find a JS only version to fetch nodes. You'd then simply iterate over the returned elements in a similar fashion.