Situation and realisations
I'm implementing a WP plugin and have to insert a new post in the wp database. So I created a form that display when the button buttonCreateInv is clicked. I use jQuery and it does work.
<?php
add_action('admin_head', 'JS_create_form_inventaire');
add_action('wp_ajax_display_form_inventaire', 'display_form_inventaire');
function button_create_inventaire(){
    echo '<button type="button" class="buttonCreateInv">Créer un inventaire</button>';
    echo '<div class="formCreateInv"></div>';
}
function JS_create_form_inventaire(){
?>
<script type="text/javascript" >
jQuery(document).ready(function($) {
    $('.buttonCreateInv').click(function(){
        $.get( 
                ajaxurl, 
                { 'action': 'display_form_inventaire' }, 
                function (result) { 
                    $(".formCreateInv").html(result); 
                }
        );    
    });
});
</script>
<?php
}
It does display my form in the function display_form_inventaire:
function display_form_inventaire() { 
   ...
   $html .='<p><label for="description">Content</label></p>'.
       '<textarea id="textareaContent" name="textareaContent" style="display:none"></textarea>'.
       '<div style="background-color:white" id="divContent" name="divContent" contenteditable="true">'.
        '<table>...</table></div>';
    $html .='<p><input type="submit" value="Créer" tabindex="6" class="submitInsert" name="submitInsert" /></p>'.
            '<input type="hidden" name="creation_inventaire" value="new_post" />'.
            wp_nonce_field( 'new-post' ).
            '</form>'.
            '</div>';
   echo $html;
}
Problem
The second time I use it, with exactly the same manner, it is not working.. 
My second jQuery which is activated on the click on the submit button submitInsert seem to not being called.
<?php
add_action('admin_head', 'JS_get_inv_content');
add_action('wp_ajax_insert_new_inventaire', 'insert_new_inventaire');
function JS_get_inv_content(){
?>
<script type="text/javascript" >
jQuery(document).ready(function($) {
    $('.submitInsert').click(function(){
        alert('test');
        $.get( 
                ajaxurl, 
                { 'action': 'insert_new_inventaire' }, 
                function (result) { 
                    alert('result');
                    //$.getElementById("textareaContent").value = $.getElementById("divContent").innerHTML;
                }
        );    
    });
});
</script>
<?php 
}
The alert test is not displayed when I click on the submitInsert button. 
 
    