In this tutorial, I’ll demonstrate how to implement conditional rules with JavaScript in Knack. Using my Classics Clips app, I’ll show you how to dynamically add a character count validation for a notes field, ensuring users can’t exceed 200 characters — all achieved with the help of ChatGPT.
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Add to JavaScript
// Validate Character Count for Client Notes for view_8$(document).on('knack-view-render.view_8', function (event, view) { // Replace with your view number
const fieldId = 'field_9'; // Replace with your field ID
const textField = $(`#${fieldId}`); // Select the text field by its ID
$('#char-count').remove(); // Remove any existing counter to prevent duplicates
const counter = $('<div id="char-count">Characters entered: 0 (maximum count is 200)</div>');
textField.after(counter); // Append the counter below the text field
const submitButton = $('.kn-button.is-primary'); // Select the button with class 'kn-button is-primary'
function updateCharCount() {
const charCount = textField.val().length;
$('#char-count').text(`Characters entered: ${charCount} (maximum count is 200)`);
if (charCount > 200) {
submitButton.prop('disabled', true); // Disable the button if the count exceeds 200
// Update colors as needed
textField.css({
'background-color': '#FBF4F5', // Set a light red background (update color as needed)
'color': '#A4454A' // Set a darker red text color (update color as needed)
});
} else {
submitButton.prop('disabled', false); // Enable the button if within the limit
// Reset styles to default if within the limit
textField.css({
'background-color': '', // Remove background color
'color': '' // Reset text color
});
}
}
updateCharCount(); // Initial count update
textField.on('input', updateCharCount); // Attach the update function
});
// Validate Character Count for Client Notes for view_204
$(document).on('knack-view-render.view_204', function (event, view) { // Replace with your view number
const fieldId = 'field_9'; // Replace with your field ID
const textField = $(`#${fieldId}`); // Select the text field by its ID
$('#char-count').remove(); // Remove any existing counter to prevent duplicates
const counter = $('<div id="char-count">Characters entered: 0 (maximum count is 200)</div>');
textField.after(counter); // Append the counter below the text field
const submitButton = $('.kn-button.is-primary'); // Select the button with class 'kn-button is-primary'
function updateCharCount() {
const charCount = textField.val().length;
$('#char-count').text(`Characters entered: ${charCount} (maximum count is 200)`);
if (charCount > 200) {
submitButton.prop('disabled', true); // Disable the button if the count exceeds 200
// Update colors as needed
textField.css({
'background-color': '#FBF4F5', // Set a light red background (update color as needed)
'color': '#A4454A' // Set a darker red text color (update color as needed)
});
} else {
submitButton.prop('disabled', false); // Enable the button if within the limit
// Reset styles to default if within the limit
textField.css({
'background-color': '', // Remove background color
'color': '' // Reset text color
});
}
}
updateCharCount(); // Initial count update
textField.on('input', updateCharCount); // Attach the update function
});
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