save-form-field-prompts.js

// Save Form Field Prompts (jQuery)
//
// If you have form fields with default values like "Enter search term"
// this code will save that value, hide it when a user focuses on the field
// and restores it when they leave the field if they didn't enter anything.

// Select the fields you want to save
var $fields = $(".commentform textarea, .commentform input.text");

// No need to change anything below here
$fields.each(function(){
	$(this)
		.data("val",$(this).val()) 	// save the initial value
		.focus(function(){
			$(this).val(''); 		// clear the field on focus
		})
		.blur(function(){
			// reset the field to the original value if the user didn't input anything
			if ($(this).val()=='') {
    			$(this).val($(this).data("val")); 
    		}
		});
});

Awesome. One thing I noticed is that if the user clicks the field (even after editing it from the original value) it sets the value to empty. It would force the user to retype a whole field if they attempt to change a field or fix a simple typo. This version fixes that.

$fields.each(function(){
    $(this)
        // save the initial value
        .data("val",$(this).val())

        // clear the value only if it has not been modified
        .focus(function(){
            if ($(this).val() == $(this).data("val")) {
                $(this).val("");
            }
        })

        // reset the field to the original value if the user didn't input anything
        .blur(function(){
            if ($(this).val() === '') {
                $(this).val($(this).data("val"));
            }
        });
});