Add a placeholder to a textfield

field-placeholder.js

jQuery(document).ready(function() {
	// Select the field we want to add the behaviour to
	var field = jQuery('#respond input[type="text"][name="ecf_4"]');
	// What text do we want to
	var placeholder_text = 'your placeholder';
	var text_changed = false;

	if ('placeholder' in field[0])
		/* Modern browsers natively support text field placeholders */
		field.attr('placeholder', placeholder_text);
	else {
		/* For older browsers we can fake it using JavaScript event handlers */

		// Set the initial text to the placeholder
		field.val(placeholder_text);

		// Keep track of whether the user has changed the text of the field
		field.change(function() {
			if (!(text_changed || $(this).val() === ''))
				text_changed = true;
			else if (text_changed && $(this).val() === '')
				text_changed = false;
		});

		// Clear the text on focus if it has not been changed by the user
		field.focus(function() {
			if (!text_changed)
				jQuery(this).val('');
		});

		// Put the placeholder back if the user has not changed the text
		field.blur(function() {
			if (!text_changed)
				jQuery(this).val(placeholder_text);
		});
	}
});