Web Development

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• January 31, 2024 at 12:36 am #4213222
  

  Error retrieving input value in window onload function

  by apn72 · about 5 days, 4 hours ago

  Tags: Software, Web development

  My html code displays a table, which includes an input (fname) which After the table, I have this script:

  window.onload = function ()
  varSepType =document.getElementById(‘fname’).value
  window.alert(varSepType );
  ChangeSName(varSepType );

  The purpose of the script is to call a function, which changes the colour of one table element. I don’t want to set the colour in the table, because the function is also called by an onChange and I want the code to not be duplicated.
  However, the console says “Uncaught TypeError: document.getElementById(…) is null”, despite the input having am initial value (it is set to a session variable & I can see on screen that it has been set).
  I’m using WordPress.
  Any ideas, please?

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• • January 31, 2024 at 4:26 am #4213240
    

    Reply To: Error retrieving input value in window onload function

    by kees_b · about 5 days, 1 hour ago

    In reply to Error retrieving input value in window onload function

    “is null” means that it doesn’t exist. And things that don’t exist don’t have a value.
    You see something else than you’re asking for. Are you using the right quotes?

    Just call the onChange routine after the form is loaded.

    • This reply was modified 5 days, 1 hour ago by kees_b.
    • This reply was modified 5 days, 1 hour ago by kees_b.
  • January 31, 2024 at 3:50 pm #4213394
    

    Reply To: Error retrieving input value in window onload function

    by benstock2244 · about 4 days, 13 hours ago

    In reply to Error retrieving input value in window onload function

    The error “Uncaught TypeError: document.getElementById(…) is null” indicates that the script is trying to retrieve an element with the specified ID (‘fname’), but it is not finding any such element in the HTML.

    Possible solutions:

    Ensure that the input element with the ID ‘fname’ is present in your HTML code.

    Check if the script is placed after the HTML content, allowing the DOM to fully load before trying to access the element.

    Ensure that there are no typos in the ID (‘fname’) and that it matches the actual ID of the input element.

    By addressing these issues, you should be able to resolve the “Uncaught TypeError” and successfully retrieve the input value in your window.onload function.

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