Styjun

Solved Needed to use the val instead of text. My mistake!

What is the difference when copying a form field to another form field vs copying a form field to a span id?

I can copy from input field to a span id no problem, but using the same method to copy from form field to another form field doesnt work.

Using Jquery keyup

Can anyone enlighten me?

Heres a Demo

Thanks in advance

 <input type="text" name="Quantity" value="100" id="quantity2" />
 <input type="text" name="Quantity" id="quantity_img2" />

 $("#quantity2").keyup(function () 
 var value = $(this).val();
 $("#quantity_img2").text(value);
 ).keyup();

To set the value of textbox element use val() method instead of text().

Working demo http://jsfiddle.net/LnDYA/20/

$("#quantity_img2").text(value);

should be

$("#quantity_img2").val(value);

DEMO

Why this happen

Because #quantity_img2 is an input field , a form element and to set value to input field require .val() method.

So your code should look like

$("#quantity2").keyup(function () 
 var value = $(this).val();
 $("#quantity_img2").val(value); // not .text()
).keyup();

Use .val() in place of .text() like this

$("#quantity2").keyup(function () 
 var value = $(this).val();
 $("#quantity_img2").val(value);
 ).keyup();

Working fiddle

I created a Jquery plugin called val2 that detects span vs input and just sorts out when to use $().text() vs. $().val(). After using val() on a span and wondering why it was broken only to slap forehead and say, "of course, dummy... its a span!" I created this plugin:

$.fn.val2 = function (newVal) 

 // Jquery Plugin to improve upon $().val() and agnostically handle get/set of values for a span or input (type="text")
 // http://learn.jquery.com/plugins/basic-plugin-creation/
 // use, get mode: var val = $("#" + id).val2(); 
 // use, set mode: $("#" + id).val2("fred"); 

 if (this !== undefined) 
 // newVal indicates set vs get mode
 if (newVal === undefined) 
 var ret = "";
 if (this.attr("value") === undefined && this.prop("value") === undefined)
 ret = this.text(); // this is a span
 else
 ret = this.val(); // this would be an input
 return ret;
 
 else 
 if (this.attr("value") === undefined && this.prop("value") === undefined)
 this.text(newVal); // this is a span
 else
 this.val(newVal); // this would be an input
 
 
;

Usage Examples:

Get mode:

var txt = $("#MySpan").val2();
var txt = $("#MyInput").val2();

Set mode:

$("#MySpan").val2("fred");
$("#MyInput").val2("fred");