h:commandButton's onclick JavaScript method dosen't run before Submitting the form

Question

hello all.I'am new to jsf.
Now i know that to set the Managed Bean attributes i can use forms, But i'm using JavaScript in my jsf page.
what i want is to execute the javascript methode onclickAdd() before submitting the form so the user can see what's changed in an anychart map of tunisia along to a table. My jsf page have a dropdown list.

   <h:form>
    Gouvernorats &#160; Temperature (C°) <br/>
     <h:selectOneMenu id="list" value="#{GouvBean.name}" >
         <f:selectItem itemValue="Tunis" itemLabel="Tunis" />
         <f:selectItem itemValue="Médenine" itemLabel="Medenine"/>
         <f:selectItem itemValue="Gabès" itemLabel="Gabès"/>
         <f:selectItem itemValue="Sfax" itemLabel="Sfax"/>
         <f:selectItem itemValue="Sidi Bou Zid" itemLabel="Sidi Bou Zid"/>
         <f:selectItem itemValue="Kassérine" itemLabel="Kassérine"/>
         <f:selectItem itemValue="Mahdia" itemLabel="Mahdia"/>
         <f:selectItem itemValue="Sousse" itemLabel="Sousse"/>
         <f:selectItem itemValue="Monastir" itemLabel="Monastir"/>
         <f:selectItem itemValue="Tataouine" itemLabel="Tataouine"/>
         <f:selectItem itemValue="Kebili" itemLabel="Kebili"/>
         <f:selectItem itemValue="Tozeur" itemLabel="Tozeur"/>
         <f:selectItem itemValue="Bèja" itemLabel="Bèja"/>
         <f:selectItem itemValue="Jendouba" itemLabel="Jendouba"/>
         <f:selectItem itemValue="Bizerte" itemLabel="Bizerte"/>
         <f:selectItem itemValue="Manubah" itemLabel="Manubah"/>
         <f:selectItem itemValue="Ben Arous" itemLabel="Ben Arous"/>
         <f:selectItem itemValue="Zaghouan" itemLabel="Zaghouan"/>
         <f:selectItem itemValue="Siliana" itemLabel="Siliana"/>
         <f:selectItem itemValue="Le Kef" itemLabel="Le Kef"/>
         <f:selectItem itemValue="Gafsa" itemLabel="Gafsa"/>
         <f:selectItem itemValue="Kairaouan" itemLabel="Kairaouan"/>
         <f:selectItem itemValue="Nabeul" itemLabel="Nabeul"/> 


     </h:selectOneMenu>

     <h:inputText id="Temperature" value="#{GouvBean.temperature}" ><f:ajax listener="#{GouvBean.inchange}"/></h:inputText>


     <h:commandButton value="+"onclick="onClickAdd();" >
        <f:ajax execute="@form"/>
    </h:commandButton>
  </h:form>

The javascript method changes a table and an AnyChart map:
this is the table:

     <table id="myTable">
         <thead><tr><th>Gouvernorats</th><th>Temperature</th>   </tr></thead>
         <tbody></tbody>

     </table>

and this is JavaScript method:

     //Define a JavaScript method
        function onClickAdd(){

            //saving the value of the list
         var Gov = document.getElementById("list");
         var Gid=Gov.options[Gov.selectedIndex];
         //deleting  the current valye(added value) from the list
                Gov.remove(Gov.selectedIndex)
         var C°=document.getElementById('Temperature');

            //Getting refrence to tbody
            var tbodyRef=document.getElementById("myTable").getElementsByTagName("tbody")[0];
            //appending a row to tbody
            var row=tbodyRef.insertRow(tbodyRef.rows.length);

            var cell1=row.insertCell(0);
            var cell2=row.insertCell(1);
            var cell3=row.insertCell(2);

            //Creation of delete button
            var del=document.createElement("BUTTON");
            var t=document.createTextNode("-");

            //Giving value to the cells 
            cell1.innerHTML=Gid.value;
            cell2.innerHTML=C°.value;
            cell3.appendChild(del);



            //adding a listener to the button   
            del.appendChild(t);
            //OnAddChangeValue(cell1.innerHTML,cell2.innerHTML);




            del.addEventListener("click",function(){

            //1)knowing the row where the button is(index)
            var x=del.parentNode.parentNode.rowIndex;
                x=x-1;

            //2)moving the value of the first cell back to the list
            var l=document.getElementById("list");

              //create option node
            var node=document.createElement("option");

              //create attribute value
            var attr1=document.createAttribute("value");

               //creation of label
            var label=document.createTextNode(tbodyRef.rows[x].cells[0].innerHTML);

                 //setting a value to the attribute
                 attr1.value=tbodyRef.rows[x].cells[0].innerHTML;

                  //linking...
                  node.setAttributeNode(attr1);
                  node.appendChild(label);
                  l.appendChild(node);
            //3)deleting the row from the tbody

                    tbodyRef.deleteRow(x);

            //  OnDeleteChangeValue(cell1.innerHTML);

            });

            }

     </script>

and this is h:head

<h:head><title>Hello world-JSF-Input Form</title>

</h:head>

help me please

NB: IT WORKS WHEN I ADD h:form before but in this case javascript dont work !

Answer 1

You use ajax in the h:selectOneMenu and h:inputText that sends the values to the server/beans already if they are in an h:form (as you found out). But instead of asking how do I send data without a form (which makes the commandButton 'work'), the question should have been

How do I prevent an h:commandButton from refreshing the page.

For which the answer is given here:

• How make commandButton not fully refresh page? How to use f:ajax?

But since you do not seem to need (or even want) to send anything to the server on clicking the (command)Button, a plain non submitting html button with an onClick would be sufficient. This can be achieved by adding type="button" to the h:commandButton (or by using the plain html counterpart which is legal too)

• What's exactly is the difference between types of h:commandbutton?

Some more general knowledge:

• commandButton/commandLink/ajax action/listener method not invoked or input value not set/updated
• Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes
• https://www.mkyong.com/jsf2/jsf-2-button-and-commandbutton-example/

Answer 2

After debugging the page in google chrome browser , i found that i need to:

1) include<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.15/proj4.js"/>

2) i realized that the id value in jsf is changed in html :

if an id of an element is "list" in jsf it becomes "j_idt6:list" in html.
so in getElmentbyid i need to do like this: document.getElementById("j_idt6:list") instead of document.getElementById("list")

now everything work fine.