How to get system.xml config values?

Question

I am trying to get the value of system.xml from a plugin I am developing.

 <field id="Moduleposition" translate="Module" type="multiselect" sortOrder="30" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Seleccionar tienda</label>
                    <source_model>Mageplaza\Simpleshipping\Model\Config\Source\ConfigOption</source_model>
</field>

From the following function I am initially trying to return a test value to show it inside an alert

 public function getSelectStore()
    {
        return "probando";
    }

I am trying to display the return of this variable within a .phtml file using Jquery.

 alert('<?php echo $block->getSelectStore(); ?>'); 

Answer 1

Try this

<?php

namespace Vendor\Module\Helper;

use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\App\Helper\AbstractHelper;
use Magento\Store\Model\ScopeInterface;
use Magento\Store\Model\StoreManagerInterface;

class Data extends AbstractHelper
{
    const XML_PATH_MODULE_CONFIG = 'section_id/group_id/field_id';

    public $_storeManager;
    public function __construct(
        StoreManagerInterface $storeManager,
        ScopeConfigInterface $scopeConfig
    ) {
        $this->_storeManager = $storeManager;
        $this->scopeConfig = $scopeConfig;
    }

    public function getConfigValue($field, $storeId = null)
    {
        return $this->scopeConfig->getValue(
            $field,
            ScopeInterface::SCOPE_STORE,
            $storeId
        );
    }

    public function getConfig($storeId = null)
    {
        return $this->getConfigValue(self::XML_PATH_MODULE_CONFIG, $storeId);
    }
}

Answer 2

Please find answer below as I assume you did not frame your question correctly.

$(document).ready(function(){ $('select[name="slider_details[slider_location]"]').change(function(){ alert( this.value ); }); });