If you want to get Simple product details of configurable product like simple product Id, sku, product name etc. you can get using my simple module.

Before using this module you need to add simple script for getting simple product id from configurable product. Check my previous post Get Simple product of configurable product.

In that script you just need to change following ajax code instead of alert box.
Note: You must need to add jQuery library in your page if library is not already added before using ajax code.

jQuery.ajax({
    type: "POST",
    url: "<?php echo $this->getBaseUrl()?>productdetails/index/optiondetails/",
    data:"id="+currentSimpleProductId,
    success: function(msg)
    {
        alert(msg);
        //var data = JSON.parse(msg);
        //alert(data.id);
    }
});

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