For a quick fix, replace the following:
wp_enqueue_script('jquery');
wp_enqueue_script('jquery-ui-core');
wp_enqueue_script('jquery-ui-tabs');
wp_enqueue_script('jquery-maskedinput',$this->uri."/js/jquery.maskedinput.js", array('jquery'));
wp_enqueue_script('jquery-cookie',$this->uri."/js/jquery.cookie.js", array('jquery'));
wp_enqueue_script('jquery-form',$this->uri."/js/jquery.form.js", array('jquery') );
wp_enqueue_script('jquery-impromptu',$this->uri."/js/jquery-impromptu.1.7.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-field',$this->uri."/js/jquery.field.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-delegate',$this->uri."/js/jquery.delegate.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-calculation',$this->uri."/js/jquery.calculation.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-tablesorter',$this->uri."/js/jquery.tablesorter.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-autogrow-textarea',$this->uri."/js/jquery.autogrow-textarea.js", array('jquery'), '1.8.0');
wp_enqueue_script('web-invoice',$this->uri."/js/web-invoice.js", array('jquery', 'jquery-ui-core', 'jquery-ui-tabs'), WEB_INVOICE_VERSION_NUM, true);
with the following:
if ($_SERVER['QUERY_STRING']=='page=web-invoice/web-invoice.php' || $_SERVER['QUERY_STRING']=='page=web_invoice_recurring_billing' || $_SERVER['QUERY_STRING']=='page=new_web_invoice' || $_SERVER['QUERY_STRING']=='page=web_invoice_templates' || $_SERVER['QUERY_STRING']=='page=web_invoice_settings')
{
wp_enqueue_script('jquery');
wp_enqueue_script('jquery-ui-core');
wp_enqueue_script('jquery-ui-tabs');
wp_enqueue_script('jquery-maskedinput',$this->uri."/js/jquery.maskedinput.js", array('jquery'));
wp_enqueue_script('jquery-cookie',$this->uri."/js/jquery.cookie.js", array('jquery'));
wp_enqueue_script('jquery-form',$this->uri."/js/jquery.form.js", array('jquery') );
wp_enqueue_script('jquery-impromptu',$this->uri."/js/jquery-impromptu.1.7.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-field',$this->uri."/js/jquery.field.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-delegate',$this->uri."/js/jquery.delegate.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-calculation',$this->uri."/js/jquery.calculation.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-tablesorter',$this->uri."/js/jquery.tablesorter.min.js", array('jquery'), '1.8.0');
wp_enqueue_script('jquery-autogrow-textarea',$this->uri."/js/jquery.autogrow-textarea.js", array('jquery'), '1.8.0');
wp_enqueue_script('web-invoice',$this->uri."/js/web-invoice.js", array('jquery', 'jquery-ui-core', 'jquery-ui-tabs'), WEB_INVOICE_VERSION_NUM, true);
}
in the file web-invoice.php
The above fixed the issue for me. Hope it will fix it for you.
Thanks,
Ahmed