How can I refresh a javascript variable, populated by JSF, via ajax? -

i want following:

1. select item h:selectonemenu
2. update backing bean new value, via ajax
3. run javascript function new value

in following code though, alert(#{backingbean.derivedvalue}) still contains value last change (i.e. it's 0 when select "two", 4 when select "one", , on):

<h:form>     <h:selectonemenu value="#{backingbean.input1}">         <f:selectitem itemlabel="one" itemvalue="1"/>         <f:selectitem itemlabel="two" itemvalue="2"/>         <f:ajax render="@form" onevent="function(data) { if (data.status === 'success') { alert(#{backingbean.derivedvalue}) }}"/>     </h:selectonemenu>      input value: #{backingbean.input1}     derived value: #{backingbean.derivedvalue} </h:form> 

and backing-bean:

@managedbean @viewscoped public class backingbean {      private int input1;     private int derivedvalue;      public int getderivedvalue() {         return derivedvalue;     }      public void setderivedvalue(int derivedvalue) {         this.derivedvalue = derivedvalue;     }      public int getinput1() {         return input1;     }      public void setinput1(int input1) {         this.input1 = input1;         derivedvalue = input1 * 2;     } } 

is there way this? (btw, i've read countless threads on site kind of/sort of deal jsf/ajax/javascript working together, not specific issue)

i had success implementing solution proposed in answer, getting backing bean value javascript uses primeface's requestcontext add javascript callback parameter server-side.

here facelets page:

<h:form>     <p:selectonemenu value="#{backingbean.input1}">         <f:selectitem itemlabel="one" itemvalue="1"/>         <f:selectitem itemlabel="two" itemvalue="2"/>         <p:ajax oncomplete="afterload(xhr, status, args)"/>     </p:selectonemenu>     <h:outputscript>         function afterload(xhr, status, args) {               alert("input * 2 = " + args.derived);         }     </h:outputscript> </h:form> 

and here backing-bean:

import javax.faces.bean.managedbean; import javax.faces.bean.viewscoped; import org.primefaces.context.requestcontext;  @managedbean @viewscoped public class backingbean {      private int input1;     private int derivedvalue;      public int getderivedvalue() {         return derivedvalue;     }      public void setderivedvalue(int derivedvalue) {         this.derivedvalue = derivedvalue;     }      public int getinput1() {         return input1;     }      public void setinput1(int input1) {         this.input1 = input1;         derivedvalue = input1 * 2;         requestcontext.getcurrentinstance().addcallbackparam("derived", derivedvalue);     } } 

(i don't know if solution integrating jsf , d3.)

see also

• getting backing bean value javascript