js+lodash js解绑定+php:解绑定函数lodash不工作

    function autocomplete_usuario_debounced(){
    
    
    		  _.debounce(autocomplete_usuario,500);
    
    	} 
    
    function autocomplete_usuario(ev) {
        $("#modal-search").css("height","500px");
        if (0 < document.getElementById("buscadora").value.length) {
            document.getElementById("auto_usuario").style.visibility = "visible";
            var a = {
                busqueda: document.getElementById("buscadora").value
            };
            $.ajax({
                type: "POST"
                , url: base_url + "/*********/********/"
                , cache: !1
                , data: a
                , success: function (response) { 
                	response = JSON.parse(response);
                	if(response['success']){
                		auto_usuario.innerHTML = response['mensaje'];
                	}
                	else{
                    	Materialize.toast('I am a toast', 2000,'',function(){ window.location.replace("/login");})
                	}
                }
            })
        }
        else{
        	document.getElementById("auto_usuario").style.visibility = "hidden", auto_usuario.innerHTML = "";
        	$("#modal-search").css("height","unset");
        }
    }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" id="buscadora" autofocus <?php if ($this->uri->segment(1) != null): ?> readonly <?php endif ?> class="input_box" name="tel_or_ced" onkeyup="autocomplete_usuario_debounced();">