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Limit number of characters in input fields without editing HTML

I'm building a database of people on a WordPress website using this plugin.
I want to limit the number of characters the user can enter in certain fields (textarea and input type="text") in the signup form. Since I'm using a plugin, I can't edit the HTML of the page, so I can't just use the maxlength attribute.
How can I limit the number of characters the user can enter - and preferably also show a remaining characters count - without access to HTML? Can you tell me which files to edit, what code to use and where to put it?

You could use jQuery to set the max length as well as append: a remaining character count
$("input").each(function() {
var $this = $(this);
var maxLength = 50;
$this.attr('maxlength', maxLength);
var el = $("<span class=\"character-count\">" + maxLength + "</span>");
el.insertAfter($this);
$this.bind('keyup', function() {
var cc = $this.val().length;
el.text(maxLength - cc);
});
});
http://jsfiddle.net/0vk3c245/
You would just need to specify which input you want to apply the function to by altering "input" on the first line as well as changing the maxLength variable based on your max characters allowed for each. You could modify this function to take in parameters for multiple fields as well.
Here is a modified version that lets you apply this to multiple inputs:
http://jsfiddle.net/0vk3c245/1/

This is really easy to do with MagJS.
Here is a full working example:
HTML :
<div id="limit">
<h2>Characters left: <length/></h2>
<input>
<textarea></textarea>
</div>
JS:
var demo = {}
demo.view = function(state, props) {
state.textarea = state.input = {
_oninput: function() {
state.length = props.limit - this.value.length;
if (this.value.length > props.limit) {
alert('max length reached:' + props.limit)
this.value = this.value.substr(0, props.limit)
}
}
}
}
var props = {
limit: 10,
}
mag.module("limit", demo, props)
Here is link to working example: http://jsbin.com/sabefizuxi/edit?html,js,output
Hope that helps!

How to set input field maxlength from label

I'm trying to figure out a way to change the maxlength of ajax called input fields by pulling the value to set out of the field's label and updating the default value. The field labels all follow the same format - id, class, type and maxlength. The new maxlength value to set is always present in the id ...max_X_characters...
`<input id="ecwid-productoption-16958710-Line_5_:0028max_4_characters:0029" class="gwt-
TextBox ecwid-productBrowser-details-optionTextField ecwid-productoption-
Line_5_:0028max_4_characters:0029" type="text" maxlength="200"></input>`
So in this example I need to set the maxlength to 4.
The other problem is that there are multiple input fields, often with different maxlength values. See here for an example.
I was thinking of setting a script to pull out the value once the fields have loaded, but I don't mind admitting it, this one's over my head - hopefully one of you bright guys n gals can figure it out!
Update: Thanks for the suggestions, I've tried both, in various combinations, but can't get them to work.
Here's the code suggested by Ecwid's tech team that sets all input fields on the page to one maxlength (6 in this case)
`Ecwid.OnPageLoaded.add(function(page){if (page.type == "PRODUCT") {
$("input.ecwid-productBrowser-details-optionTextField").attr('maxlength','6');
};
})`
However, as I stated there are input fields with different maxlengths for some products.
I've tried replacing the '6' above with a function, based on your suggestions, to get the maxlength from the input id, but can't get it to work.
Any more ideas?
Thanks
Update:
Cracked it (nearly), here's the working code
`Ecwid.OnPageLoaded.add(function(page){
var regex = new RegExp("max_(\\d+)_characters");
var inputs = document.getElementsByTagName("input");
for (var i = 0; i < inputs.length; i++) {
var inp = inputs[i];
if (regex.test(inp.id)) {
var newLimit = inp.id.match(regex)[1];
inp.maxLength = newLimit;
}
}
});`
Thanks so much for your help, it works like a dream on the product page but there is another area where it doesn't. A customer can edit the input text via a pop-up, from the shopping basket.
The fields have similar code:
`<input id="ecwid-productoption-16958710-Line_5_:0028max_4_characters:0029"
class="gwt-TextBox ecwid-productBrowser-details-optionTextField ecwid-productoption-
Line_5_:0028max_4_characters:0029" type="text" maxlength="200"></input>`
Suggestions very welcome
Chris
UPDATE:
Many, many, many thanks to ExpertSystem (you genius you!) - I think we've got it. (tested on IE10, firefox 21, chrome 27).
The code below is for people using Yola and Ecwid together, but I guess the original code may work for people using other sitebuilders. It limits the number of characters a user can enter into input fields, in Ecwid, by checking for a number in the input field's title (in this case the value between 'max' and 'characters') and replacing that as the field's maxLength value. It limits fields in the product browser, in the html widgets and in the cart pop-up.
Here it is:
Go to Yola's Custom Site Tracking Code section. In the 'Footer Code' column (actually placed at the bottom of the 'body'), place this code:
<script>
Ecwid.OnPageLoaded.add(function(page){
var regex = new RegExp("max_(\\d+)_characters");
var inputs = document.getElementsByTagName("input");
for (var i = 0; i < inputs.length; i++) {
var inp = inputs[i];
if (regex.test(inp.id)) {
var newLimit = inp.id.match(regex)[1];
inp.maxLength = newLimit;
}
}
});
</script>
<script>
var regex = new RegExp("max_(\\d+)_characters");
function fixMaxLength(container) {
var inputs = container.getElementsByTagName("input");
for (var i = 0; i < inputs.length; i++) {
var inp = inputs[i];
if (regex.test(inp.id)) {
var newLimit = inp.id.match(regex)[1];
inp.maxLength = newLimit;
}
}
};
</script>
and this into the 'Header Code' column:
<script>
document.addEventListener("DOMNodeInserted", function() {
var popups = document.getElementsByClassName("popupContent");
for (var i = 0; i < popups.length; i++) {
fixMaxLength(popups[i]);
}
});
</script>
That's it! You're good to go.

It is not exactly clear what is meant by "ajax called input fields", but supposing that the input fields are created and added to DOM inside a success callback for some AJAX call, you can place the following piece of code in your pages <head>:
var regex = new RegExp("max_(\\d+)_characters");
function fixMaxLength(container) {
var inputs = container.getElementsByTagName("input");
for (var i = 0; i < inputs.length; i++) {
var inp = inputs[i];
if (regex.test(inp.id)) {
var newLimit = inp.id.match(regex)[1];
inp.maxLength = newLimit;
}
}
}
And then, at the end of the AJAX call's "onSuccess" callback, append this:
fixMaxLength(document);
UPDATE:
Based on your comments below, if you need to apply fixMaxLength() to div's of class "popupContent", which get dynamically added to your DOM, an easy way (not the most efficient though) would be adding a listener for DOM modification events (e.g. somewhere in <head>):
document.addEventListener("DOMNodeInserted", function() {
var popups = document.getElementsByClassName("popupContent");
for (var i = 0; i < popups.length; i++) {
fixMaxLength(popups[i]);
}
});
(NOTE: I have only tested it on latest versions of Chrome and Firefox, so I am not really sure for which other/older browsers this does work.)
(NOTE2: GGGS, has tested it (and found it working) on IE10 as well.)

How about a regular expression on your id attribute? Such as the following:
jQuery('input').each(function() {
var idVal = jQuery(this).attr('id');
var regex = /max_(\d+)_characters/g;
var result = regex.exec(idVal);
var length = result[1];
});
This is a loop over all the inputs. Once this is run, the length variable will have the proper length each go through, for your next step.

changing text for a selected option only when its in selected mode

I am not sure if I confused everyone with the above title. My problem is as follows.
I am using standard javascript (no jQuery) and HTML for my code. The requirement is that for the <select>...</select> menu, I have a dynamic list of varying length.
Now if the length of the option[selectedIndex].text > 43 characters, I want to change the option[selectecIndex] to a new text.
I am able to do this by calling
this.options[this.selectedIndex].text = "changed text";
in the onChange event which works fine. The issue here is once the user decides to change the selection, the dropdownlist is showing the pervious-selected-text with changed text. This needs to show the original list.
I am stumped! is there a simpler way to do this?
Any help would be great.
Thanks

You can store previous text value in some data attribute and use it to reset text back when necessary:
document.getElementById('test').onchange = function() {
var option = this.options[this.selectedIndex];
option.setAttribute('data-text', option.text);
option.text = "changed text";
// Reset texts for all other options but current
for (var i = this.options.length; i--; ) {
if (i == this.selectedIndex) continue;
var text = this.options[i].getAttribute('data-text');
if (text) this.options[i].text = text;
}
};
http://jsfiddle.net/kb7CW/

You can do it pretty simply with jquery. Here is a working fiddle: http://jsfiddle.net/kb7CW/1/
Here is the script for it also:
//check if the changed text option exists, if so, hide it
$("select").on('click', function(){
if($('option#changed').length > 0)
{
$("#changed").hide()
}
});
//bind on change
$("select").on('change', function(){
var val = $(":selected").val(); //get the value of the selected item
var text = $(':selected').html(); //get the text inside the option tag
$(":selected").removeAttr('selected'); //remove the selected item from the selectedIndex
if($("#changed").length <1) //if the changed option doesn't exist, create a new option with the text you want it to have (perhaps substring 43 would be right
$(this).append('<option id="changed" value =' + val + ' selected="selected">Changed Text</option>');
else
$('#changed').val(val) //if it already exists, change its value
$(this).prop('selectedIndex', $("#changed").prop('index')); //set the changed text option to selected;
});

How to get all radio buttons inside a table?

i have group of radio buttons inside a table along with other inputs in this table, and i can't get the radio buttons by id or name or by tag name, i want to get them by type if this possible, because id and name is auto generated by JSF, and i don't want to change this.
so the requirement is: get all radio buttons only (not all inputs) inside the table so i can loop on them.

I hope there's only one set of radio buttons. In that case something like this can help:
var inputs = yourForm.elements;
var radioes = [];
for (var i = 0; i < inputs.length; ++i) {
if (inputs[i].type == 'radio') {
radioes.push(input[i]);
}
}​
In case there are more than one set of radio buttons, better approach would be to have a dictionary with the name as the key and the value as the array of radio buttons in the group.

I know the question doesn't mention jQuery, but I just wanted to demonstrate the simplicity of it; please consider this more of a selling point of "hey, look how nice jQuery is".
// look how pretty I am
var radioButtons = $('table#MyTableId input[type="radio"]');

Given your form name is yourForm ... (<form name = "yourForm">) ... an easy way is just to parse all form elements and check for the type, something like this:
var your_namespace = {};
your_namespace.your_function = function() {
var l = document.yourForm.elements.length;
for (i=0; i<l; i++) {
var type = yourForm.elements[i].type;
if (type=="radio") alert("Form element " + i + " is a radio!");
}
}
Instead of alerting you can ofc do alot of other things with the element id.
You can have this way easier when using a framework like MooTools or JQuery.

Limit the number of children in a form using Javascript

I am trying to limit the number of additional form input fields that a user can add dynamically to a file upload form to just 3. The form is loaded with one static input field and through javascript can add additional fields with an add button or remove additional form input fields with a remove button. Below is the html in it's static form.
<fieldset>
<legend>Upload your images</legend>
<ol id="add_images">
<li>
<input type="file" class="input" name="files[]" />
</li>
</ol>
<input type="button" name="addFile" id="addFile" value="Add Another Image" onclick="window.addFile(this);"/>
</fieldset>
With javascript I would like to create a function where the number of child elements are counted and if the number is equal to three then the "Add Another Image" button becomes disabled. In addition, if there are three elements in the form the user - with the remove button - removes a child then the "Add Another Image" button becomes enabled again.
I think I'm may be missing some crucial lines of code. The below javascript code only allows me to add one additional input field before the Add Another Image button becomes disabled. Removing this field with the remove file button removes the field but the Add Another Image button is still disabled. Below is where I'm currently at with the javascript.
function addFile(addFileButton) {
var form = document.getElementById('add_images');
var li = form.appendChild(document.createElement("li"));
//add additional input fields should the user want to upload additional images.
var f = li.appendChild(document.createElement("input"));
f.className="input";
f.type="file";
f.name="files[]";
//add a remove field button should the user want to remove a file
var rb = li.appendChild(document.createElement("input"));
rb.type="button";
rb.value="Remove File";
rb.onclick = function () {
form.removeChild(this.parentNode);
}
//create the option to dispable the addFileButton if the child nodes total "3"
var nodelist;
var count;
nodelist = form.childNodes;
count = nodelist.length;
for(i = 0; i < count; i++) {
if (nodelist[i] ==3) {
document.getElementById("addFile").disabled = 'true';
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = 'false';
}
}
}

Oh, OK, I've tested out the code now and see a couple of problems:
You're counting the number of child elements but this includes the text elements so there's actually one for the <li> and one for the text within it.
You've enclosed the true/false setting for the disabled property in quotes but it doesn't work and always set's it to false.
The remove button doesn't re-enable the add button.
I found this to work:
function addFile(addFileButton) {
var form = document.getElementById('add_images');
var li = form.appendChild(document.createElement("li"));
//add additional input fields should the user want to upload additional images.
var f = li.appendChild(document.createElement("input"));
f.className="input";
f.type="file";
f.name="files[]";
//add a remove field button should the user want to remove a file
var rb = li.appendChild(document.createElement("input"));
rb.type="button";
rb.value="Remove File";
rb.onclick = function () {
form.removeChild(this.parentNode);
toggleButton();
}
toggleButton();
}
function toggleButton() {
var form = document.getElementById('add_images');
//create the option to dispable the addFileButton if the child nodes total "3"
var nodelist;
var count;
nodelist = form.childNodes;
count = 0;
for(i = 0; i < nodelist.length; i++) {
if(nodelist[i].nodeType == 1) {
count++;
}
}
if (count >= 3) {
document.getElementById("addFile").disabled = true;
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = false;
}
}

I would suggest a slightly different approach. Create all three file input fields statically and provide a clear button. If the user chooses to leave it empty they can. If that is not elegant use your "Remove" to simply hide the field (CSS style display: none;).

I'm not sure why you're using the for loop? Shouldn't it be like this:
var nodelist = form.childNodes;
if (nodelist.length >= 3) {
document.getElementById("addFile").disabled = 'true';
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = 'false';
}

The last part of that function is a bit strange. Technically, when adding fields, you should only be disabling the button (i.e. you could never enable the button by adding fields). I would suggest removing the for loop and going with:
var count = form.getElementsByTagName("li").length;
if(count == 3)
document.getElementById("addFile").disabled = true;
The reason the add field button is still disabled when you remove an item is because you don't re-enable the add field button when you click remove. Try this for the remove button click handler:
rb.onclick = function () {
form.removeChild(this.parentNode);
document.getElementById("addFile").disabled = false;
}