How to auto populate the lookup field value into the text field in visualforce page?

Question

I am trying to auto populate the value of lookup field to text field in the visualforce page. As soon as I select the value of lookup field from the list the value as it get populated in the lookup field also it need to get populated in the text field which I have created in the visualforce page. Can I achieve this functionality ?

Here Daily_Record__c is my custom object I want to auto populate the value of <apex:inputfield value="{!Daily_Record__c.Username__c}"/> in to the <apex:inputText value="{!strAccSearchString}"/> so what should I do ?

apex code :-

 <apex:page Standardcontroller="Daily_Record__c" extensions="ctrlSearch">
<apex:form >  
  <apex:inputfield value="{!Daily_Record__c.Username__c}"/>
    <apex:inputText value="{!strAccSearchString}"/>>
     <apex:commandButton value="Search" action="{!SearchAccountRec}"/>       
      <apex:pageBlock rendered="true" title="Search Result">
        <apex:pageBlockTable value="{!lstAccount}" var="acc">
         <apex:column >
          <apex:facet name="header">Name</apex:facet> 
        <apex:outputLink value="/{!acc.id}">{!acc.Username__c} 
           </apex:outputLink>        
            </apex:column>  
            <apex:column >
            </apex:column>                    
        </apex:pageBlockTable>          
    </apex:pageBlock>
    <apex:pageBlock rendered="{!If(lstAccount.size==0 && isResultDisplay == 
          true,true,false)}" title="Search Result">           
        <apex:pageblockSection >
            <apex:outputLabel value="No Result Found"></apex:outputLabel>
        </apex:pageblockSection>
      </apex:pageBlock>
    </apex:form>
 </apex:page>

Answer 1

There are two ways of doing this that I know of. One is to write a controller extension. If you use a controller extension, it should be straightforward to create a method that passes the lookup Id using a getter which then sets the text.

The other, which may or may not be simple depending on your skills would be to call Javascript you've written using a CommandLink via OnClick. Your JS will then need to take the value of !Daily_Record__c.Username__c, convert it to a string and populate <apex:inputText value="{!strAccSearchString}"/> with it before calling a refresh on that section of the page (If User is pre-populated, your JS could do all this running your JS 'OnInit').