selectlist and javascript in VF page

<apex:form >
<apex:outputLabel value="Type" />
<br/>
<apex:selectList id="Lista" value ="{!type1}" size="1">
    <apex:selectOptions value="{!Types}"/>
</apex:selectList>
<br/>
<div class="typesSection"></div>
<apex:outputLabel value="First/Last Name" />
<br/>
<apex:inputText value="{!searchText}" id="searchText"></apex:inputText>
<apex:commandButton value="change" onClick="change()"/>
</apex:form>

<script>
    function change(Lista){

        ss = document.getElementById(Lista).value;
        alert(ss);
    }
</script>Hi everybody,
I am trying to populate selectlist options through onload javascript function, but some how this is not working. I have pasted the code below that iam working on, could any body please suggest any changes to make it working.
<apex:page >
<script> window.onload = list1;
function list1()
{
var list=document.getElementById('listchosen');
for(var i=0;i<10;i++)
list.add(new Option('xxx','xxx'));
}
</script>
<apex:outputPanel id="result"> <apex:form >
<b>Please select :</b>
<apex:selectList id="listchosen" multiselect="false" size="1"> </apex:selectList>
</apex:form>
</apex:outputPanel>
</apex:page><apex:selectList styleclass="Lista" value ="{!type1}" size="1">
    <apex:selectOptions value="{!Types}"/>
</apex:selectList>

var e = document.getElementsByClassName("Lista")[0];
var strUser = e.options[e.selectedIndex].value;You have to modify your list1 method.

1. SFDC generated ids at run time for the apex tags. Please use correct Id of the apex:selectList.

2. You should add the Option to options list of the html element.

 

Please check the below code -

function list1()

{

var list=document.getElementById('j_id0:j_id2:listchosen');

for(var i=0;i<10;i++)

list.options.add(new Option(i,i));

}