javascript within asp.net framework, document.getElementbyId error

[phpmel]

hi guys,

here is my problem. i have a js function called changemsg that takes a label in an aspx page and sets its text to blank.

<script type="text/javascript" >
        function changemsg(lbl){
            document.getElementById(lbl).innerHTML=" ";
        }
</script>
 

on the page load method of my page, i call the function as follows

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            manuTextBox.Attributes.Add("onFocus", "changemsg('ctl00_ContentPlaceHolder1_manuLabel');");
            wcTextBox.Attributes.Add("onFocus", "changemsg('ctl00_ContentPlaceHolder1_wcLabel');");
            vmTextBox.Attributes.Add("onFocus", "changemsg('ctl00_ContentPlaceHolder1_descLabel');");
 
        }
    }
 

i am using master pages, that is why i am saying 'ctl00_ContentPlaceHolder1_descLabel' instead of plain descLabel etc.
Also, it is worth noting that i am calling the same function with different labels.

my problem is that if i Enable script Debugging in internet explorer, when the page loads, the message is
"document.getElementById(...)' is null or not an object"

even if i disable script Debugging in internet explorer, the status bar would say "done but with errors" and that is the error behind it

how can i fix the problem
is my code correct?

[gits]

please have a look at or post the generated html-code ... and check whether the ids are correct or not ... or give a link to a testpage.

kind regards

[phpmel]

thank you for you suggestion,

i did view the generated source code and what i discovered was that there was no code for the labels since i had initially set them to be NOT visible, so when the page is loaded it was causing the error. i set the labels visible=true and i believe it is working now.

thank you so much. i am going to play around with it a little bit and if anything else occurs, i will post back

thank you again

[gits]

no problem ... ;) post back when you have more problems with it ...

kind regards