[Javascript] Combine 2 form fields into one.

5,619 · January 28, 2013

I've got a credit card form and on submission it requires that the expiry date is submitted from a single string as mmyy. Instead, the form is mm and yy in separate submission boxes.

I figured it would be possible to take the two value's and combine them by sitcking them into a hidden field.

I found a script online and due to my very limited knowledge of javascript I wouldn't actually know what to do with this and it looks looks somewhat incomplete:

<script language=javascript>

funtion populate(){

Fname = document.form1.FirstName.value;

Lname = document.form1.LastName.value;

document.form1.CONTACT.value = Fname + " " + Lname;

}

</Script>

Then call the function with onchange on your lastname field <input ID="LastName" value="" onChange="populate()"

I'm completely full of cold at the moment so my brains not firing on all thrusters.

Would this require any library like jquery to work?

If there's a way to do this without javascript that would be even better. Thing is as the forms being submitted via a thirdparty api I don't have the luxury of combining them via PHP at form submission.

Appreciate any help.

Many thanks.

Alex

7,409 · January 28, 2013

No, it's simple.

<script type="text/javascript">
function join_ym()
{
var yy = document.getElementById('yy').value;
var mm = document.getElementById('mm').value;
document.getElementById('joint').value = yy+mm;
alert(document.getElementById('joint').value);
}
</script>

<input type="text" id="yy" />
<input type="text" id="mm" />
<input type="hidden" id="joint">
<input type="button" value="Join!" onclick="join_ym();">[/CODE]

Edit:

Time to explain. First we have a form with an id called 'yy'. We get its value through the [b]document.getElementById('id_name').value[/b] javascript function. Replace id_name with the id of the text input.

We do the same for mm. We get its value through the document.getElementById('mm').value, whereas mm is the text input's id.

We then assign the value to the hidden form, which I called [u][b]joint [/b][/u] through the same procedure as I took the other two's (mm and yy) value.

We do this again with the [b]document.getElementById('joint').value = [/b]function and operator, whereas joint is the id of hidden form.

For concatenating strings, I used the [b]+[/b] operator. Which joined the yy and mm variables together, forming a new string.

At the end, I used alert, to throw at screen what is the value of [b]joint, [/b]my hidden form.

I hope I've been clear, anything else just ask.

Edit #2. Since you seem to have PHP knowledge, the [b]+[/b] operator is analog to the [b].[/b] (dot) in PHP

5,619 · January 28, 2013

Thanks for this! I'm not at home right now so will implement this in the morning.

Would adding the function to the onclick operator on the submit button ensure that the appropriate hidden field was populated prior to the form being submitted? Or would it be best to have the relevant field updated as and when those fields are filled out?

Again, many thanks!

January 29, 2013

Here you go:


<html>
<head>
</head>
<body>
  <form action="" method="get">
   <input type="text" name="name_first" placeholder="First Name" oninput="join_names();" onpaste="join_names();" /><br />
   <input type="text" name="name_last" placeholder="Last Name" oninput="join_names();" onpaste="join_names();" /><br />
   <input type="text" name="name_full" placeholder="Full Name" /><br />
   <input type="submit" onclick="join_names();" />
  </form>
  <script type="text/javascript">
   function concatenate(/*String*/string_one, /*String*/string_two, /*boolean*/with_space) {
    if (with_space===true) {
	 return string_one+' '+string_two;
    }
    else {
	 return string_one+string_two;
    }
   }
   function join_names() {
    var input_name_first = document.getElementsByName('name_first')[0].value;
    var input_name_last = document.getElementsByName('name_last')[0].value;
    var input_name_full = document.getElementsByName('name_full')[0];
    var var_name_full = concatenate(input_name_first, input_name_last, true);
    input_name_full.value = var_name_full;
   }
  </script>
</body>
</html>
[/CODE]

This will not only update the code with every key they press, but also eliminates the need for ids for your elements if you don't want them. This works solely off of the name attribute of your inputs which is a bit cleaner and more useful if you are styling your inputs similarly (using classes instead of ids). Also, I added the ability to concatenate the strings with or without a space, and made it cross browser compatible. Hopefully you find this useful!

Also, if you plan on using a textarea, change the oninput attribute to textInput. :)

5,619 · January 29, 2013

Thanks fellas.

I combined elements from both methods to a nice simple scripts which seemingly does what I wanted. I based it mostly off Jose_49's method because it seemed simpler for me to achieve but if I've overlooked something please let me know:


&lt;input id="expiry" type="hidden" name="field18317078" value="" /&gt;


&lt;input id="month" class="tiny" placeholder="mm" type="text" oninput="join_expiry();" onpaste="join_expiry();"&gt;
&lt;input id="year" class="tiny" placeholder="yy" type="text" oninput="join_expiry();" onpaste="join_expiry();"&gt;


&lt;script type="text/javascript"&gt;
function join_expiry()
{
var mm = document.getElementById('month').value;
var yy = document.getElementById('year').value;
document.getElementById('expiry').value = mm+yy;
}
&lt;/script&gt;

7,409 · January 29, 2013

Thanks fellas.

I combined elements from both methods to a nice simple scripts which seemingly does what I wanted. I based it mostly off Jose_49's method because it seemed simpler for me to achieve but if I've overlooked something please let me know:
&lt;input id="expiry" type="hidden" name="field18317078" value="" /&gt;


&lt;input id="month" class="tiny" placeholder="mm" type="text" oninput="join_expiry();" onpaste="join_expiry();"&gt;
&lt;input id="year" class="tiny" placeholder="yy" type="text" oninput="join_expiry();" onpaste="join_expiry();"&gt;


&lt;script type="text/javascript"&gt;
function join_expiry()
{
var mm = document.getElementById('month').value;
var yy = document.getElementById('year').value;
document.getElementById('expiry').value = mm+yy;
}
&lt;/script&gt;

No probs.

Be careful with the oninput, placeholder methods. They are HTML5 and only modern browsers support it.

5,619 · January 29, 2013

So I suppose it's best to add the function on submit too? Would "onclick" work with older browsers?

January 29, 2013

No probs.

Be careful with the oninput, placeholder methods. They are HTML5 and only modern browsers support it.

So I suppose it's best to add the function on submit too? Would "onclick" work with older browsers?

Well, the onpaste (which is not html5) has support accross IE, Firefox, Safari, and Chrome. The oninput is a more up-to-date method, and also adds support for Opera. By combining them, it is very unlikely that you will have any issues at all.

Thanks for pointing that out though. :)

March 15, 2018

I have to say... THANK YOU!!!!!! Awesome how it worked like a charm to me! really THANK YOU!!!!!!!! i have implemented this into RsForm Pro with joomla! with a little variation to fit my forms.

My case was:
Create a user name field (one field of the form) based on two form field filled by the user, with a special caracter dividing the two captured field forms data.
Apart, the JS to do the trick of join two field into one, will be ran only if the user select to create the account selecting a checkbox field and if not nothign will be done.

<script type="text/javascript">
function copy(){
  //This is the check box option where i want if selected, the data to be copied to the form field "test"
if (document.getElementById("copy0").checked==true)
    
    {
var cupon = document.getElementById('cupon').value;
var celular = document.getElementById('celular').value;
//Agregue un signo '-' al resultado compilado y agregue un signo + al segundo valor.
document.getElementById('test').value = cupon+'-'+celular;
alert(document.getElementById('test').value);
    }
    //my checkbox got two options. So first one is "copy0" second one is "copy1" and if they choose secondone, no copy will be done.
    else if (document.getElementById("copy1").checked==true)
    
    {
    document.getElementById("cupon").value="";
    document.getElementById("celular").value="";
    }
    
}
</script>

XHTML 
<fieldset class="formFieldset">
<legend>{global:formtitle}</legend>
{error}
<!-- Do not remove this ID -->
<ol class="formContainer" id="Trend_{global:formid}_page_0">
	<li class="block-cupon">
		<div class="formCaption">{cupon:caption}<strong class="formRequired">(*)</strong></div>
		<div class="formBody">{cupon:body}<span class="formClr">{cupon:validation}</span></div>
		<div class="formDescription">{cupon:description}</div>
	</li>
	<li class="block-descphone">
		<div class="formCaption">{DescPhone:caption}</div>
		<div class="formBody">{DescPhone:body}<span class="formClr">{DescPhone:validation}</span></div>
		<div class="formDescription">{DescPhone:description}</div>
	</li>
	<li class="block-celular">
		<div class="formCaption">{celular:caption}<strong class="formRequired">(*)</strong></div>
		<div class="formBody">{celular:body}<span class="formClr">{celular:validation}</span></div>
		<div class="formDescription">{celular:description}</div>
	</li>
	<li class="block-email">
		<div class="formCaption">{email:caption}<strong class="formRequired">(*)</strong></div>
		<div class="formBody">{email:body}<span class="formClr">{email:validation}</span></div>
		<div class="formDescription">{email:description}</div>
	</li>
	<li class="block-test">
		<div class="formCaption">{test:caption}</div>
		<div class="formBody">{test:body}<span class="formClr">{test:validation}</span></div>
		<div class="formDescription">{test:description}</div>
	</li>
	<li class="block-copy">
		<div class="formCaption">{copy:caption}<strong class="formRequired">(*)</strong></div>
		<div class="formBody">{copy:body}<span class="formClr">{copy:validation}</span></div>
		<div class="formDescription">{copy:description}</div>
	</li>


</ol>
</fieldset>

Really thank you so much dude @Jose_49!

Quote

what tipe of course do you suggest to learn more about this? Jose_49

Edited March 15, 2018 by DavidDem

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[Javascript] Combine 2 form fields into one.

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