如何在jQuery中获取动态创建的文本框的动态ID

Question

i want to perform keyup event via textbox id, and all textbox are dynamically created with onclick button event. for this i have to make 20 keyup function. if i use 20 keyup function then my code will become too lengthy and complex. instead of this i want to use a common function for all textbox. can anybody suggest me how to do it..thanks

here is what i am doing to solve it:

<div class="input_fields_wrap">
<button class="add_field_button">Add Booking</button></div>
<div id='TextBoxesGroup'>
    <div id="TextBoxDiv1">
    </div>
    </div>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script> 
<script>
$(document).ready(function() {
    var counter = 2;
    $(".add_field_button").click(function() {
        if (counter > 10) {
            alert("Only 10 textboxes allow");
            return false;
        }

        var newTextBoxDiv = $(document.createElement('div'))
            .attr("id", 'TextBoxDiv' + counter);

        newTextBoxDiv.after().html('<div id="target"><label>Textbox #' + counter + ' : </label>' +
            '<input type="text" name="textbox' + counter +
            '" id="firsttextbox' + counter + '" value="" >&nbsp;&nbsp;<input type="text" name="textbox' + counter +
            '" id="secondtextbox' + counter + '" value="" >  <a href="#" id="remove_field">Remove</a><input type="text" id="box' + counter + '" value="">sum</div>');
        newTextBoxDiv.appendTo("#TextBoxesGroup");

        counter++;

    });

    function check(a, b) {
        var first = a;
        var second = b;
        var temp = temp;
        var novalue = "";
        result = parseInt(first) + parseInt(second);
        if (!isNaN(result)) {
            return result;
        } else {
            return novalue;
        }
    }


    $(this).on("keyup", "#firsttextbox2", function(e) {
        e.preventDefault();
        var a = document.getElementById('firsttextbox2').value;
        var b = document.getElementById('secondtextbox2').value;
        var number = 2;
        result = check(a, b);
        document.getElementById('box2').value = result;

    });

    $(this).on("keyup", "#firsttextbox3", function(e) {
        var number = 3;
        e.preventDefault();
        var a = document.getElementById('firsttextbox3').value;
        var b = document.getElementById('secondtextbox3').value;
        result = check(a, b);
        document.getElementById('box3').value = result;
    });

    $(this).on("keyup", "#firsttextbox4", function(e) {
        var number = 4;
        e.preventDefault();
        var a = document.getElementById('firsttextbox4').value;
        var b = document.getElementById('secondtextbox4').value;
        result = check(a, b);
        final = document.getElementById('box4').value = result;
    });

    $(this).on("keyup", "#secondtextbox2", function(e) {
        e.preventDefault();
        var a = document.getElementById('firsttextbox2').value;
        var b = document.getElementById('secondtextbox2').value;

        result = check(a, b);
        document.getElementById('box2').value = result;

    });

    $(this).on("keyup", "#secondtextbox3", function(e) {
        e.preventDefault();
        var a = document.getElementById('firsttextbox3').value;
        var b = document.getElementById('secondtextbox3').value;
        result = check(a, b);

        document.getElementById('box3').value = result;
    });

    $(this).on("keyup", "#secondtextbox4", function(e) {
        e.preventDefault();
        var a = document.getElementById('firsttextbox4').value;
        var b = document.getElementById('secondtextbox4').value;
        result = check(a, b);

        document.getElementById('box4').value = result;
    });


    $(this).on("click", "#remove_field", function(e) { //user click on remove text
        e.preventDefault();
        $(this).parent('#target').remove();
        counter--;

    });


});
</script>

Answer 1

See the snippet below to see how you can make this implementation more modular and useable. The trick is to think: what do I want to do? I want to be able to add multiple inputs and add their value, printing the result in another input.

It comes down to using classes - since we are going to use the same kind of thing for every row. Then apply something that works for all classes. No IDs whatsoever! You can even use the name property of the input that contains the value you want to save. Using the [] in that property will even pass you back a nice array when POSTING!

I know this looks like a daunting lot, but remove my comments and the number of lines reduces dramatically and this kind of code is almost infinitely extendable and reusable.

But have a look, this works and its simple and - most of all - it's DRY ( don't repeat yourself 0 once you do, re-evaluate as there should be a better way!)!

Update

You could also use a <ol> as a wrapper and then add an <li> to this every time, so you get automatic counting of boxes in the front end without any effort from your end! Actually, thats so nice for this that I have changed my implementation.

 var add = $('#add_boxes'); var all = $('#boxes'); var amountOfInputs = 2; var maximumBoxes = 10; add.click(function(event){ // create a limit if($(".box").length >= maximumBoxes){ alert("You cannot have more than 10 boxes!"); return; } var listItem = $('<li class="box"></li>'); // we will add 2 boxes here, but we can modify this in the amountOfBoxes value for(var i = 0; i < amountOfInputs; i++){ listItem.append('<input type="text" class="input" />'); } listItem.append('<input type="text" class="output" name="value" />'); // Lets add a link to remove this group as well, with a removeGroup class listItem.append('<input type="button" value="Remove" class="removeGroup" />') listItem.appendTo(all); }); // This will tie in ANY input you add to the page. I have added them with the class `input`, but you can use any class you want, as long as you target it correctly. $(document).on("keyup", "input.input", function(event){ // Get the group var group = $(this).parent(); // Get the children (all that arent the .output input) var children = group.children("input:not(.output)"); // Get the input where you want to print the output var output = group.children(".output"); // Set a value var value = 0; // Here we will run through every input and add its value children.each(function(){ // Add the value of every box. If parseInt fails, add 0. value += parseInt(this.value) || 0; }); // Print the output value output.val(value); }); // Lets implement your remove field option by removing the groups parent div on click $(document).on("click", ".removeGroup", function(event){ event.preventDefault(); $(this).parent(".box").remove(); }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script> <ol id="boxes"> </ol> <input type="button" value="Add a row" id="add_boxes" /> 

Answer 2

You can target all your textboxes, present or future, whatever their number, with a simple function like this :

 $(document).on("keyup", "input[type=text]", function(){ var $textbox = $(this); console.log($textbox.val()); }) $("button").click(function(){ $("#container").append('<input type="text" /><br>'); }) 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div id="container"> <input type="text" /><br> <input type="text" /><br> <input type="text" /><br> </div> <button>Create one more</button> 

You don't need complicated generated IDs, not necessarily a class (except if you have other input[type=text] you don't want to conflict with). And you don't need to duplicate your code and write 20 times the same function. Ever . If you're duplicating code, you're doing wrong.

Answer 3

Providing a code-snippet which may give you some hint:

$(".add_field_button").click(function () 
{
    if (counter > 10) 
    {
        alert("Only 10 textboxes allow");
        return false;
    }
    var txtBoxDiv = $("<div id='TextBoxDiv"+counter+"' style='float:left;width:10%; position:relative; margin-left:5px;' align='center'></div>");

     //creating the risk weight
     var txtBox1 = $('<input />', 
                           {
                            'id'     : 'fst_textbox_' + counter,
                            'name'   : 'textbox'+counter,
                            'type'   : 'text',
                            'class'  : 'input_field',
                            'onClick' : 'txtBoxFun(this,'+counter+')'
                          });
     var txtBox2 = $('<input />', 
                           {
                            'id'     : 'sec_textbox_' + counter,
                            'name'   : 'textbox'+counter,
                            'type'   : 'text',
                            'class'  : 'input_field',
                            'onClick' : 'txtBoxFun(this,'+counter+')'
                          });

    var txtBox3 = $('<input />', 
                           {
                            'id'     : 'sum_textbox_' + counter,
                            'name'   : 'textbox'+counter,
                            'type'   : 'text',
                            'class'  : 'input_field',
                          });

 $(txtBoxDiv).append(txtBox1).append(txtBox2);
 $(txtBoxDiv).append(txtBox3);
});

function txtBoxFun(obj, count)
{
   var idGet = $(obj).attr('id');
   var idArr = new Array();
   idArr = idGet.split("_");
   if(idArr[0] == "fst")
   {
      var sumTxt = parseInt(parseInt($(obj).val()) + parseInt($("#sec_textbox_"+count).val()));
   }
   else if(idArr[0] == "sec")
   {
      var sumTxt = parseInt(parseInt($(obj).val()) + parseInt($("#fst_textbox_"+count).val()));
   }
   $("#sum_textbox_"+count).val(sumTxt);

}

Answer 4

You can assign a class to all textboxes on which you want to perform keyup event and than using this class you can attach the event on elements which have that class . Here is an example

var html="";
for (var i = 0; i < 20; i++)
 {
   html += "<input type='text' id='txt" + i + "' class='someClass' />";
 }
 $("#testDiv").html(html);

Attach keyup event on elements which have class someClass .

 $(".someClass").keyup(function () {
  alert($(this).attr("id"));
 });

Answer 5

A little helper to combine with your favorite answer:

var uid = function () {
    var id = 0;
    return function () {
        return ++id;
    };
}();

Usage:

uid(); // 1
uid(); // 2
uid(); // 3

Answer 6

Add classes "a" and "b" to the textboxes and "box" to the box. Then add data-idx attribute with the index (unused!?). Finally register the event handlers:

 $('.a').on('keyup', function(e){
    e.preventDefault();
    var $this = $(this)
    var $p = $this.parent()
    var a= this.value; 
    var b= $p.find('.b').val()
    var number =$this.data('idx') //unused!?
    var result = check(a,b)
    $p.find('.box').val(result)
 })
 $('.b').on('keyup', function(e){
    e.preventDefault();
    var $this = $(this)
    var $p = $this.parent()
    var a= $p.find('.a').val()  
    var b= this.value
    var result = check(a,b)
    $p.find('.box').val(result)
 })

Or a general one:

 $('.a,.b').on('keyup', function(e){
    e.preventDefault();
    var $p = $(this).parent()
    var a= $p.find('.a').val()  
    var b= $p.find('.b').val()
    var result = check(a,b)
    $p.find('.box').val(result)
 })