Develop Reference

Unexpected JS behavior when clearing input field value - STCombobox

I am using some JQuery Combobox that you can check out here: https://simpletutorials.com/uploads/1860/demo/index.html
As you can see, you can start typing and get the results filtered.
However, once you have selected a value, when clicking on the arrow to open the list, no other values are shown anymore. So, if I want to change college/state, I need to manually clear the input value. I don't like this, so I want to modify it.
I changed that code and added this JS on the click event of the list:
onclick="document.getElementById('statesCombo-ddi').value='';"
This line basically finds the input by id and sets its value to an empty string.
You can try out by looking for the td element having class "stc-button" (with Chrome, just focus on the arrow of the second combo box) and add my code to the tag.
===EDIT===
You can obtain the same results by adding this code directly to the input:
onclick="this.value=''"
===END EDIT===
This has a weird behavior:
If I SELECT an element from the list, it clears the value and everything works correctly.
If I TYPE some letters and then select a value from the list, no item is shown in the list after clicking.
What's wrong with it?

You can override one of the combo box methods to accomplish this:
STComboBox.prototype.filterAndResetSelected = function() {
this.$('ddi').val('');
this.filterList('');
this.selectRow(0);
this.$('ddl').scrollTop(0);
};
Does this help?
The unminified code is provided, is relatively small (12kb) and is fairly well commented, so you could make this modification directly to the source if you'd like.
Edit: Fixed to clear the input value (as indicated in the comment below)

By reading the source and doing a little debugging with Chrome's inspector (Control+Shift+i), you can find the particular ID of the element you need to clear (#collegesCombo-ddi) in order to clear the input box. Once you've found the element's ID you need to clear (and being very careful with plugins that assign multiple elements with the same ID, which is not allowed in the standard, and an indicator of poorly-written code):
$('#collegesCombo-ddi').val('');

Set Value of Hidden Field in SharePoint using jQuery

I am able to set the value of a site column (field), using jQuery, when it is not hidden using this:
$("select[Title='MyID']").val(MyRelatedID);
However, once I hide the field it doesn't work. I inspected the code and it looks like SharePoint hides it from the source code as well. I am opening the list containing the fields in a modal. Has anyone be able to set the hidden value of field?

I usually use this approach:
To set the value:
$('input[title="MyID"]').attr("value",MyRelatedID);
To hide the field:
$('input[title="MyID"]').parent().parent().parent().css("display","none");
I documented the complete approach here.

html input displays different text to value that it posts

I am feeling really stupid and not sure if doing something really dumb what... so excuse me in advance.
I have the following HTML:
<input type="text" value="0" name="pcscubes" id="pcscubes">
I have the below jquery syntax:
var cubes=123.2;
$("#pcscubes1").val(cubes);
var test=$("#pcscubes1").val();
alert(test);
When the jquery executes, the input box will display 123.2 and the alert will be 123.2.
if you inspect the html object though, the value is still 0?
so the display of the input is different from what the real value is. so when I submit this form it posts 0 rather than 123.2
Now I have built a whole web app with this syntax and works perfectly. today it just stops working? I have restarted browser, checked old code that was working, logged off and on and still it does the same.
web app obviously has jquery loaded and jquery ui on this form.
using codeigniter?
any ideas as I am banging my head over something so stupid....
Out of interest I created the below fiddle and it is doing the same?
http://jsfiddle.net/49nqU/
why is the value 0 when it is showing 123.2?
Thanks as always,

This is a case of attributes vs. properties.
What you are seeing in the inspector is the value attribute, which does not update when you programmatically update a field's value property.
Pay no attention to what the DOM inspector says; it'll only show the value as it was when the page loaded (unless you explicitly change the field's value attribute rather than, as jQuery's val() does, its value property.)
Further reading: http://jquery-howto.blogspot.co.uk/2011/06/html-difference-between-attribute-and.html
Some attributes are closely tied to their property counterparts. That is to say, updating the property also updates the attribute. This is the case, for example, with the class attribute and its className property counterpart. value, however, is different; updating the property does not update the attribute (but, just to confuse things further, updating the attribute does update the property!)

val() is changing the value property, not attribute. The value attribute is initialized at the loading of the page. Once you change text field the value property and attribute have differnet values.
But you can use plain JS for changing the value attribute also.
Try:
var cubes=123.2;
document.getElementById('qty').setAttribute('value',cubes);
var test=$("#qty").val();
alert(test);
DEMO

How to hide an HTML input field with javascript

I need to hide a text input field with javascript. Changing its type attribute to hidden does not work in IE (security issue).
What would be the best way to do it?
Note: No jQuery or other lib can be assumed.

I assume you have to show and hide the text field dynamically based on changing conditions in the form, otherwise you'd just make it an <input type="hidden"... to begin with.
Keep your code that shows and hides the field as it is, but also catch the onsubmit event.
In the submit handler, get your text field via document.getElementById(...) (or by accessing document.forms[i]) and check to see whether or not it's hidden.
If it is hidden, create a new DOM node for an <input type="hidden" ...> field and add that node to the form, probably via myform.appendChild(...). You'll have to give it the name your server-side code expects. Copy the contents of the hidden text field into the newly created type=hidden field, then return from your submit handler, allowing the standard submit to continue.
You could also just un-hide the text field on submit, but you'd have to move it "off screen" also or the user would see it reappear during submit processing.

Try wrapping it in a div or span and then setting the display style to none when you want to hide it, and then to block (if you used a div) or inline (if you used a span) when you want to show it.

document.myform.myelement.style.display = 'none'
works as expected even in Internet Explorer.

The only way you can change it is before you append it to the DOM. You can make a new element and then replace the current one with it.
Look at replaceChild and createElement since you want to do manual DOM scripting. I assume you know what to do.
EDIT: "Hidden" fields as far as I know are sent. Have you checked whether they are? And you can also just do position:absolute; left:-9999em; to offset them.

reload a page without losing field values like in FireFox using javascript

I'm very new to JavaScript and HTML.
I have a simple html form that has some select fields. When the user selects the options from the fields, a function is called that takes the values of the fields, multiples the values against other field values and spits out the results to an input text field named "result".
This is all working great, however I would love a way that instead of outputting the results to a text field, it would output as standard text on the page.
What I did was call the calculate function the tag, within the body, I inserted a document.write(result), then I created a button that calls the calculate function in addition to location.reload().
In Firefox, it works perfectly where it KEEPS the options selected, calculates the results, reloads the page and updates the document.write(result) value on the page.
But in IE or Safari, it resets the select options values to the default settings.
I hope this makes sense and appreciate any help!

how about this:
every time the user selects an option, or makes any sort of a selection, serialize that control, and slap the serialized string to the end of the current window.location, then navigate to it.
also, you will need to add javascript to check the current url, figure out what selection was made, and pro grammatically change the control's values. this way, when the user refreshes the page, the url will contain all of his selections.
got it?

Instead of document.write you could setup an element used specifically to hold the output value much like you do currently with the input element.
In place of the current input element used to output the result..
<span id="calculationResult"></span>
Then to populate that value and avoid reloading the page at all so that your fields maintain current values..
document.getElementById("calculationResult").innerHTML = result;
if you need to append you can always just create text nodes and append to the element which would be preferred anyway.

In order to keep text boxes' content as is, set the button as type="button" and call the calculate function and document.write in onclick. No reload, no mess.