<form action="" method="">

    <input type="file" id="file">

    <label for="file">上传图片</label>

    <img src="" alt="" id="myimg"/>

</form>

#file{

    display: none;

}

#file + label{

    display: inline-block;

    width: 100px;

    height: 30px;

    background-color: rgb(90, 152, 222);

    text-align: center;

    line-height: 30px;

    border-radius: 5px;

}

img{

    display: none;

    width: 200px;

    height: 200px;

}

var myimg = document.getElementById('myimg');

var file = document.getElementById('file');

file.onchange = function(){

    var url;

    var agent = navigator.userAgent;   //检测浏览器版本

    if (agent.indexOf("MSIE")>=1) {

      url = file.value;

    } else if(agent.indexOf("Firefox")>0) {

      url = window.URL.createObjectURL(file.files.item(0));

    } else if(agent.indexOf("Chrome")>0) {

      url = window.URL.createObjectURL(file.files.item(0));

    }

    myimg.src = url

    myimg.style.display = "block";

}