单击动态添加的按钮时，函数调用仅工作一次

Question

OK so I have a button that was dynamically added to my HTML form. When I click this button the JQuery below runs. There is a function call to checkLimit() which just basically returns a number so I know which textbox to display. The function works great the first time, but the second time it only gets to the checkLimit() call and quits. It doesn't even call the function(I tested this by having alerts pop up you will see these are commented out below):

JQUERY: all inside of $(document).ready(function()

for (var i = 0; i < 25; i++){
$("#Add_").on("click", "#plus_"+i, function(){
      checkLimit();

        if (checkLimit = 1){
        var txtbox = "<div id='Div_2_Int"+i+"'> <label> <br> </label> "
            + "<input type='text' id='Txtbox_2_Int_"+i+"' name=Txtbox_2_Int_"+i+ "'value=''>";


            $('.addSys').append(txtbox);
           }
        else if(checkLimit = 2){
        var txtbox = "<div id='Div_3_Int"+i+"'> <label> <br> </label> "
        + "<input type='text' id='Txtbox_3_Int_"+i+"' name=Txtbox_3_Int_"+i+ "'value=''>";

        $('.addSys').append(txtbox);

        }

});

}

Javascript function:

var num4 = 2;
function checkLimit() {
//alert("test2");
    if(num4 >= 4){
        alert("Only 3!");
    }else if(num4 == 3){
            num4++;
            return 2;                
    }else if(num4 == 2){
            num4++;
            return 1;
    }
    }

Answer 1

Two errors in your if clauses, eg:

if (checkLimit = 1){

Replace this with:

if(checkLimit()===1){

Otherwise the variable checkLimit holding your function does not get called, but overwritten with the value 1. Additionally if you want to compare values, use the comparance operator ("===" or "==") and not the assignment operator ("="). Be aware of the differences of the comparance operators, too.

Answer 2

You are not assigning the return value of checkLimit(); to a variable.

Try: var checkLimit = checkLimit();

Also, what's the point of that function if you're not passing any parameters and using a global var?