基于现有JS代码实现下拉框选中校验弹窗需求求助

Hey fellow JS beginner! Let's update your PreSaveAction function to include the dropdown check you need. Here's how to do it step by step:

Modified Complete Code #

function PreSaveAction() {
    // Original attachment validation logic
    var elm = document.getElementById("idAttachmentsTable");
    if (elm == null || elm.rows.length == 0) {
        document.getElementById("idAttachmentsRow").style.display = 'none';
        alert("Please attach Documents");
        return false;
    }

    // New dropdown validation logic
    // Replace "YOUR_DROPDOWN_ID" with the actual ID of your dropdown element
    var dropdown = document.getElementById("YOUR_DROPDOWN_ID");
    // Check if dropdown exists and selected value is not "123"
    if (dropdown && dropdown.value !== "123") {
        alert("Please select the option with value '123'");
        return false;
    }

    // All validations passed, allow form submission
    return true;
}

Key Explanations #

• Keep existing attachment check first: We run the original validation first—if no attachments are found, we immediately show the alert and block submission, no need to check the dropdown.
• Target the dropdown: Replace YOUR_DROPDOWN_ID with the actual id attribute of your dropdown (you can find this using browser dev tools by right-clicking the dropdown and selecting "Inspect").
• Safe check for dropdown existence: We add dropdown && before checking the value to avoid console errors if the dropdown element can't be located (a solid robustness practice).
• Value matching: We compare the dropdown's selected value to "123"—if your dropdown's option uses a numeric value instead of a string, remove the quotes and use 123 instead.

Quick Tip #

If you're unsure about the dropdown's ID, inspect the element in your browser's dev tools and look for the id attribute in the HTML (it’ll look like <select id="exampleDropdown">...</select>).

内容的提问来源于stack exchange，提问作者nhdy