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Editorial Team
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Asked: 2026-05-22T15:26:22+00:00

Problem: Sometimes you will want to access a component from javascript with getElementById ,

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Problem: Sometimes you will want to access a component from javascript with
getElementById, but id’s are generated dynamically in JSF, so you
need a method of getting an objects id. I answer below on how you can do this.

Original Question:
I want to use some code like below. How can I reference the inputText JSF component in my Javascript?

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:f="http://java.sun.com/jsf/core">
    <head>
       <title>Input Name Page</title>
        <script type="javascript" >
          function myFunc() {
            // how can I get the contents of the inputText component below          
            alert("Your email address is: " + document.getElementById("emailAddress").value);
          }
       </script>
    </head>
    <h:body>
        <f:view>
            <h:form>
                Please enter your email address:<br/>
                <h:inputText id="emailAddresses" value="#{emailAddresses.emailAddressesStr}"/>
                <h:commandButton onclick="myFunc()" action="results" value="Next"/>
            </h:form>
        </f:view>
    </h:body>
</html>

Update: this post Client Identifiers in JSF2.0 discusses using a technique like:

<script type="javascript" >
  function myFunc() {
    alert("Your email address is: " + document.getElementById("#{myInptTxtId.clientId}").value);
  }
</script>

<h:inputText id="myInptTxtId" value="backingBean.emailAddress"/>
<h:commandButton onclick="myFunc()" action="results" value="Next"/>

Suggesting that the attribute id on the inputText component
creates an object that can be accessed with EL using #{myInptTxtId},
in the above example. The article goes on to state that JSF 2.0 adds
the zero-argument getClientId() method to the UIComponent class.
Thereby allowing the #{myInptTxtId.clientId} construct suggested
above to get the actual generated id of the component.

Though in my tests this doesn’t work. Can anyone else confirm/deny.
The answers suggested below suffer from drawback that the above
technique doesn’t. So it would be good to know if the above technique
actually works.

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1 Answer

  1. Editorial Team

    Answer: So this is the technique I’m happiest with. Doesn’t require doing too much weird stuff to figure out the id of a component. Remember the whole point of this is so you can know the id of a component from anywhere on your page, not just from the actual component itself. This is key. I press a button, launch javascript function, and it should be able to access any other component, not just the one that launched it.

    This solution doesn’t require any ‘right-click’ and see what the id is. That type of solution is brittle, as the id is dynamically generated and if I change the page I’ll have to go through that nonsense each time.

    1. Bind the component to a backing bean.

    2. Reference the bound component wherever you want.

    So here is a sample of how that can be done.

    Assumptions: I have an *.xhtml page (could be *.jsp) and I have defined a backing bean. I’m also using JSF 2.0.

    *.xhtml page

    <script>
  function myFunc() {
    var inputText = document.getElementById("#{backBean.emailAddyInputText.clientId}")                 
    alert("The email address is: " + inputText.value );
  }
</script>

<h:inputText binding="#{backBean.emailAddyInputText}"/>
<h:commandButton onclick="myFunc()" action="results" value="Next"/>

    BackBean.java

    UIInput emailAddyInputText;

    Make sure to create your getter/setter for this property too.

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