Error get name value copy from textarea

    <script>    
    $(document).ready(function(){
            $('.next').click(function(){
                $('input#productname').val($('input#_productname').val()); 
                $('textarea#description').val($('textarea#_description').val());
            }); 
        });
    </script>

    <input type="text" name="_productname" id="_productname" value="demo"/>
    <textarea name="_description" id="_description" value="demo" ></textarea>
    <input type="text" name="productname" id="productname" />
    <textarea name="description" id="description" ></textarea>
     <input id="next" class="next" type="submit" name="next开发者_开发知识库" value="next" />

output:

productname = demo 
description =

Help me get value this tag texterea

Textareas do not have a value attribute ^{documentation} (so do not use one). You have to put the value between the opening and closing tag <textarea> value here </textarea>

and also id's cannot start with _ ^documentaion so change that too, and it should work.

html

<input type="text" name="productname_" id="productname_" value="demo"/>
<textarea name="description_" id="description_">demo</textarea>
<input type="text" name="productname" id="productname" />
<textarea name="description" id="description" ></textarea>

javascript

$(document).ready(function(){
        $('.next').click(function(){
            $('input#productname').val($('input#productname_').val()); 
            $('textarea#description').val($('textarea#description_').val());
        }); 
    });

demo at http://jsfiddle.net/gaby/Fmxyd/

I really don't know what yo are trying to do but instead of this:

$('input#productname').val($('input#_productname').val()); 
$('textarea#description').val($('textarea#_description').val());

You should just do:

$('#productname').val($('#_productname').val()); 
$('#description').val($('#_description').val());

If you have an ID, then thats all you need.