jquery - Pass a javascript variable through a hidden input -

okay, have javascript calculate dynamic price html form. code follows:

jquery("input[name='amount']").change(function() { if (isnan(parsefloat(this.value)) || !isfinite(this.value)) { jquery(this).val(''); return false; } var calc = parsefloat(this.value) * 0.95; jquery(this).parents("form").find("input[name='price']").val(calc); }); 

this, input:

<input class="irrelevant typeahead" type="text" placeholder="amount" name="amount"/> 

the javascript takes value, calculates price, , want fill this:

<input type="hidden" name="price" value=""/> 

i believe javascript correct. need price make work?

make sure have these items wrapped in <form> tag.

<form>     <input class="irrelevant typeahead" type="text" placeholder="amount" name="amount"/>     <br />     <input type="hidden" name="price" value=""/> </form>   jquery("input[name='amount']").change(function() {     if (isnan(parsefloat(this.value)) || !isfinite(this.value)) {         jquery(this).val('');         return false;     }     var calc = parsefloat(this.value) * 0.95;     jquery(this).parents("form").find("input[name='price']").val(calc); }); 

i have working demo here: http://jsfiddle.net/p55ge/

in demo have made price input text field instead of hidden field ease of seeing value being set.

also note, field updated when enter valid number , click off field input. following quote jquery documentation .change() http://api.jquery.com/change/

now when second option selected dropdown, alert displayed. displayed if change text in field , click away. if field loses focus without contents having changed, though, event not triggered.