本文实例为大家分享了JavaScript实现单图片上传并预览功能的具体代码，供大家参考，具体内容如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>单图片上传并实现预览</title>
<style>
/*上传图片*/
.addPerson{
line-height: 190px;
}
.addPhoto{
width: 50px;
height: 50px;
line-height: 50px;
font-size: 40px;
text-align: center;
vertical-align: middle;
border: 1px dashed #e7eaec;
cursor: pointer;
display: inline-block;
}
.addinput{
display: none;
}
.addShow{
width: 200px;
height: 170px;
display: inline-block;
vertical-align: middle;
background: #f3f3f48f;
margin-left: 30px;
}
.addShow img{
width: 130px;
height: 130px;
margin: 20px auto;
display: block;
}
</style>
</head>
<body>
<div class=" addPerson">
<label class="col-sm-2 control-label">图片上传</label>
<div class="col-sm-9" style="display: inline-block;">
<div class="addPhoto">+</div>
<div class="addinput">
<input type="file" class="addFile" onchange="previewFile()" name="sPicture">
</div>
<div class="addShow" style="position: relative">
<img src="" class="addImg" alt="">
</div>
</div>
</div>
</body>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
<script>
$(".addPhoto").click(function () {
$('[type=file]').click();
});
function previewFile() {
var preview = document.getElementsByClassName("addImg")[0];
var file = document.getElementsByClassName('addFile')[0].files[0];
var reader = new FileReader();
reader.addEventListener("load", function () {
preview.src = reader.result;
}, false);
if (file) {
reader.readAsDataURL(file);
}
// ajax请求如下
// 使用FormData将图片以文件的形式传到后台
// pictureFile后台接收的参数
// var formdata=new FormData();
// formdata.append("pictureFile",addFile);
// $.ajax({
// url:"",
// type:"post",
// dataType:"json",
// data:formdata,
// async: false, //四个false属性不能少
// cache: false,
// contentType: false,
// processData: false,
// success:function (data) {
// if(data.success){
// myAlert(data.msg);
// }
// },
// error:function () {
// if(data.success){
// myAlert(data.msg);
// }
// }
// })
}
</script>
</html>
