Enable/Disable button using dynamically added checkbox's

HTML

<form id="goalForm"> 
    <input type="text" id="goalId" />
    <input id="enterBtn" value="Enter" type="button" disabled="disabled"/>
    <input id="deleteBtn" value="Remove" type="button" disabled="disabled"/>&nbsp;&nbsp;
    <input id="completeBtn" value="Complete" type="button" disabled="disabled"/>
    <input id="clearBtn" value="Clear all" type="button" disabled="disabled"/>
</form>

<div class="panel" id="log_data">
    <h3>Tasks</h3>
</div>

<div class="panel" id="output">
    Output:
</div>

JavaScript

$(function () {
    
    var completeBtn = el("completeBtn");
    var enterBtn    = el("enterBtn");
    var clearBtn    = el("clearBtn");
    var deleteBtn   = el("deleteBtn");
    var inItemText  = el("goalId");
    var form        = el("goalForm");
    var logData     = el("log_data");
    var output      = el("output");
    var totalItems  = 0;
    var checked     = 0;
    
    function el(i){
       return document.getElementById(i); 
    }
    
    function processMe(val){
        if (!val || val == " ") {
            return disableFunction(enterBtn);
        }
        return enableFunction(enterBtn);
    }
    
    enterBtn.onclick = function(){
        btn1();
    } 
    
    deleteBtn.onclick = function(){ 
        delCheckedBoxes();
    }
    
    completeBtn.onclick = function(){ 
        submitBoxes();
    }
    
    clearBtn.onclick = function(){ 
        clearBoxes();
    }
    
    inItemText.onchange = function(){
        processMe(this.value);
    }
    
    inItemText.onkeypress = function(evt){
        var keyCode = evt ? (evt.which ? evt.which : evt.keyCode) : event.keyCode;
        if (keyCode == 13) {
            btn1();
            return false;
        }
        processMe(this.value);  
    }
    
    inItemText.onpaste = function(){
        processMe(this.value);
    }
    
    inItemText.oninput = function(){
        processMe(this.value);
    }
    
    function disableFunction(btn) {
        btn.disabled = true;
    }
    
    function enableFunction(btn) {
        btn.disabled = false;
    }
    
    function checkSpanStatus() {
        alert("path works");
    } 
    
    function updateItemStatus() {
        var cbId = this.Id.replace("cb_","");
        var itemText = document.getElementById("item_" + cbId);
        if(this.checked) {
            itemText.style.textDecoration = "line-through";
            checked++;
        }else{
            itemText.style.textDecoration = "none";
            checked--;
        }
        if(checked...