How to do multiple file upload validation using JS/Mootools/JQuery?

Question

hi all busy developers, I had a form in which two elements are there -

<form> 
   <table id="nwtbl" width="100%">
<tr>
    <td>
        <select name="prof_img_type[]">
            <option value="">Select Image Caption</option> 
                <option value="a">ABC</option> 
                <option value="x">XYZ</option> 
                <option value="p">PQR</option> 
        </select>
    </td>
    <td>
        <input type="file" name="prof_img[]" onblur="chkext(this.value,['jpg','jpeg','png']);"/>
    </td> 
</tr>
<tr>
    <td>
        <input type="button" value="Add Row" onclick="adnwrw();" />
    </td>
    <td>
        <input type="button" value="Delete Row" onclick="dlrw();" />
    </td>
</tr>

here the validation function called on event onblur of file element is working fine. User can add append elements (i.e prof_img_type[] and prof_img[]) dynamically. An User must Select image type & upload file if he adds a row(s). How to do this validation before submitting form. I hope i have given simple description. Thanks in advance.