How to add multiple divs with appendChild?

问题

I am trying to make a chessboard using javascript and creating 64 divs with it.
The problem is, that it creates only the first div.
Here is the code:

div {
    width: 50px;
    height: 50px;

    display: block;
    position: relative;
    float: left;
}

<script type="text/javascript">
    window.onload=function()
    {
        var i=0;
        var j=0;
        var d=document.createElement("div");

        for (i=1; i<=8; i++)
        {
            for (j=1; j<=8; j++)
            {
                if ((i%2!=0 && j%2==0)||(i%2==0 && j%2!=0))
                {
                    document.body.appendChild(d);
                    d.className="black";
                }
                else
                {
                    document.body.appendChild(d);
                    d.className="white";
                }
            }
        }
    }
</script>

回答1:

The problem is, that it creates only the first div.

Right, because you've only created one div. If you want to create more than one, you must call createElement more than once. Move your

d=document.createElement("div");

line into the j loop.

If you call appendChild passing in an element that's already in the DOM, it's moved, not copied.

window.onload=function()
    {
        var i=0;
        var j=0;

        for (i=1; i<=8; i++)
        {
            for (j=1; j<=8; j++)
            {
                if ((i%2!=0 && j%2==0)||(i%2==0 && j%2!=0))
                {
                    var d=document.createElement("div");
                    document.body.appendChild(d);
                    d.className="black";
                }
                else
                {
                    var d=document.createElement("div");
                    document.body.appendChild(d);
                    d.className="white";
                }
            }
        }
    }

回答2:

As t-j-crowder has noted, the OP's code only creates one div. But, for googlers, there is one way to append multiple elements with a single appendChild in the DOM: by creating a documentFragment.

function createDiv(text) {
  var div = document.createElement("div");
  div.appendChild(document.createTextNode(text));
  return div;
}

var divs = [
  createDiv("foo"),
  createDiv("bar"),
  createDiv("baz")
];

var docFrag = document.createDocumentFragment();
for(var i = 0; i < divs.length; i++) {
  docFrag.appendChild(divs[i]); // Note that this does NOT go to the DOM
}

document.body.appendChild(docFrag); // Appends all divs at once

回答3:

Although what T.J. Crowder writes works fine, I would recommend rewriting it to the code below, using a documentFragment, like Renato Zannon suggested. That way you will only write to the DOM once.

    window.onload = function() {
        var count = 5,
            div,
            board = document.getElementById('board'),
            fragment = document.createDocumentFragment();
        
        // rows
        for (var i = 0; i < count; ++i) { 

            // columns
            for (var j = 0; j < count; ++j) { 
                div = document.createElement('div');
                div.className = (i % 2 != 0 && j % 2 == 0) || (i % 2 == 0 && j % 2 != 0) ? 'black' : 'white';
                fragment.appendChild(div);
            }
        }
        
        board.appendChild(fragment);
    };

#board {
  background-color: #ccc;
  height: 510px;
  padding: 1px;
  width: 510px;
}

.black,
.white {
    float: left;
    height: 100px;
    margin: 1px;
    width: 100px;
}

.black {
  background-color: #333;
}

.white {
  background-color: #efefef;
}

<div id="board"></div>

回答4:

function crt_dv(){
dv=document.createElement('div'),document.body.appendChild(dv)
};

crt_dv(),dv.className='white';crt_dv(),dv.className='black';

Also use: for(i=0;i<2;i++)

来源：https://stackoverflow.com/questions/14910196/how-to-add-multiple-divs-with-appendchild

标签

javascript

appendchild