js 上传图片文件，限制格式、大小和尺寸
通过js限制上传图片
前言
做前端项目时，经常会用到form表单，偶尔也会用到input标签来提交上传图片文件。在上传文件时，有时候会有一定的条件，比如图片格式、大小及尺寸。
通过js，可以在前端来设置上传图片的格式、尺寸及大小，并验证。
主要方法
1、设置上传图片的格式
jsp代码，设置form表单的input标签
<input type="file" id="file" name="file" onchange="verificationPicFile(this);verificationPicFile1(this)" >
onchange属性：在域的内容改变时发生。
js代码，设置图片的格式
//验证上传文件的格式 function verificationPicFile(file) { var fileTypes = [".jpg", ".png", ".jpeg", ".PNG", ".gif"];//文件后缀只能是这五类 var filePath = document.getElementById("file").value;//返回的是上传文件的路径名 例如：E:\xx\xxx.jpg //当括号里面的值为0、空字符、false 、null 、undefined的时候就相当于false if(filePath){ var isNext = false; var fileEnd = filePath.substring(filePath.indexOf("."));//截取文件名的后缀 for (var i = 0; i < fileTypes.length; i++) { if (fileTypes[i] == fileEnd) { isNext = true; break; } } if (!isNext){ alert('不接受此文件类型'); document.getElementById("file").value = "";//如果文件后缀名不符合，清空已选择文件 return false; } }else { return false; } }
2、设置上传图片的大小
//图片大小验证 function verificationPicFile(file) { var fileSize = 0; var fileMaxSize = 1024;//1M var filePath = file.value; if(filePath){ fileSize =file.files[0].size; var size = fileSize / 1024; if (size > fileMaxSize) { alert("文件大小不能大于1M！"); file.value = ""; return false; }else if (size <= 0) { alert("文件大小不能为0M！"); file.value = ""; return false; } }else{ return false; } }
3、设置上传图片的尺寸
//图片尺寸验证 function verificationPicFile1(file) { var filePath = document.getElementById("file"); /*alert(filePath.files) 返回Object FileList*/ if(filePath.files){ //读取图片数据 var f = filePath.files[0];//返回Object File var reader = new FileReader(); //通过FileReader类型读取文件中的数据（异步文件读取） reader.onload = function (e) { var data = e.target.result; //返回文件框内上传的对象 //加载图片获取图片真实宽度和高度 var image = new Image(); image.onload = function(){ var width = image.width; var height = image.height; alert('文件像素宽：' + width +'，文件像素高：'+ height + '文件大小：'+f.size + '字节'); if (width == 295 & height == 413){ alert("文件尺寸符合！"); }else { alert("文件尺寸应为：295*413（像素）！"); document.getElementById("file").value = ""; return false; } }; image.src= data; //img.src 应该是放在 onload 方法后边的, 因为当image的src发生改变，浏览器就会跑去加载这个src里的资源,先告诉浏览器图片加载完要怎么处理，再让它去加载图片 }; reader.readAsDataURL(f);//读取文件并将文件数据以URL形式保存到result属性中。 读取图像常用 }else{ return false; } }
亲测有效：
// 原生JS onload 是异步函数，上传图片接口必须写在里面，不能放外面 const fileNameChanged = function() { var files = document.querySelector('input[type="file"]').files; console.log('files', files[0]) const file = files[0] // 控制大小,这里根据需要自行设置 if (file.size > 1024*1024*5) { toastr.warning("限制5M内图片上传") return } // 控制尺寸 let widthPix = $scope.deviceInfo.inScreen.width let heightPix = $scope.deviceInfo.inScreen.height console.log('背景图片像素', widthPix, heightPix) var reader = new FileReader(); //通过FileReader类型读取文件中的数据（异步文件读取） reader.onload = function (e) { var data = e.target.result; //返回文件框内上传的对象 //加载图片获取图片真实宽度和高度 var image = new Image(); image.onload = function(){ var width = image.width; var height = image.height; if (width == widthPix && height == heightPix){ // 尺寸正确，执行下面的函数 console.log('参数', $rootScope.equipmentId, $rootScope.projectCode) var form = new FormData(); form.append('equipmentId', $rootScope.equipmentId) form.append('projectCode', $rootScope.projectCode) form.append('imgFile', files[0]) $http({ method: 'POST', url: '/jsis/uploadPicture', data: form, headers: {'Content-Type': undefined}, transformRequest: angular.identity }).success(function (response) { console.log('upload success111111', response); $scope.bgImgWidget.data.value = response.data $scope.imageSrc = response.data $('#upload-img').attr('src', response.data) $('#bgImgSrc').attr('src', response.data) $scope.bgImgUrlDay = response.data // 白天模式 $scope.bgImgUrlNight = response.data // 黑夜模式 var imgIndex = $scope.devices[$scope.curIndex].widgets.findIndex(el => el.type == 2) $scope.devices[$scope.curIndex].widgets[imgIndex].data.value = response.data }).error(function (data) { console.log('upload fail'); }) }else { // alert("文件尺寸应为：295*413（像素）！"); toastr.warning('图片尺寸不符合，图片尺寸应为：'+ widthPix+'*'+heightPix+'(像素)') document.querySelector('input[type="file"]').value = ""; return false; } }; image.src= data; //img.src 应该是放在 onload 方法后边的, 因为当image的src发生改变，浏览器就会跑去加载这个src里的资源,先告诉浏览器图片加载完要怎么处理，再让它去加载图片 }; reader.readAsDataURL(file);//读取文件并将文件数据以URL形式保存到result属性中。 读取图像常用 };
elementUI el-upload检测图片尺寸代码如下：
<template>
<div v-loading="isLoading" class="uploadImg-globalParams">
<el-upload
:class="{'hideUpload': fileList.length>0, 'showUpload': fileList.length==0}"
ref="upload"
action="#"
:http-request="handleFileUpload"
list-type="picture-card"
:headers="headers"
accept="image/*"
:on-preview="handlePictureCardPreview"
:on-remove="handleRemove"
:on-success="handleSuccess"
:before-upload="beforeAvatarUpload"
:on-exceed="handleExceed"
:file-list="existFileList">
<!-- <el-button size="small" type="primary">点击上传</el-button> -->
<i class="el-icon-plus" style="width:70px;height:70px;line-height:67px;"></i>
<!-- <template slot="trigger">
<i v-show="showUploadBtn" class="el-icon-plus" style="width:70px;height:70px;line-height:67px;"></i>
</template> -->
<div slot="tip">
<p class="tips" v-html="remark"></p>
</div>
</el-upload>
<div v-show="isEdit">
<i class="el-icon-check icon-check" @click="editParamValue()"></i>
<i class="el-icon-close icon-close" @click="cancleDelete"></i>
</div>
<el-dialog :visible.sync="dialogVisible" append-to-body>
<img width="100%" :src="dialogImageUrl" alt="">
</el-dialog>
</div>
</template>
<script>
import jportalCommon from '@/jportal-common-update'
import {uploadPicture} from '@/api/park'
let userStorageService = jportalCommon.userStorageService
export default {
props: {
limit: {
type: Number,
default: 9,
required: false
},
type: {
type: String,
default: 'V'
},
requestUrl: {
type: String,
default: "/jpark-cloud-center/api/jsis/park/uploadPicture",
// default: "/jpark-center-mgr/api/jsis/upload/upload2oss",
required: false
},
projectCode: {
type: String,
default: ''
},
imgInfo: {
type: Object,
default: function(){return {}},
required: false
},
// existFileList: {
// type: Array,
// default: function () {
// return [
// // {url: 'https://fuss10.elemecdn.com/3/63/4e7f3a15429bfda99bce42a18cdd1jpeg.jpeg?imageMogr2/thumbnail/360x360/format/webp/quality/100'},
// // {url: 'https://fuss10.elemecdn.com/3/63/4e7f3a15429bfda99bce42a18cdd1jpeg.jpeg?imageMogr2/thumbnail/360x360/format/webp/quality/100'}
// ]
// },
// required: false
// },
tips: {
type: String,
default: '*请先选择小区才可上传图片'
},
acceptImgType: {
type: Array,
default: function () {
return ["image/jpeg", "image/png"]
},
required: false
}
},
data() {
return {
isLoading: false,
//上传文件
headers: {
'orgCode': userStorageService.getUser().orgCode,
'personId': userStorageService.getUser().personId,
'personName': encodeURIComponent(userStorageService.getUser().personName),
'jsToken': userStorageService.getToken().jsToken,
'jsCurAccNo': userStorageService.getToken().jsCurAccNo
},
dialogImageUrl: '',
dialogVisible: false,
// 上传的图片
fileList: [],
// 删除之前的图片
removeList: [],
isEdit: false,
supportFileWidth: '',
supportFileHeight: '',
remark: '',
existFileList: [],
showUploadBtn: false
}
},
mounted () {
// this.fileList = []
},
methods: {
downloadFile(url, name) {
let path = "/jpark-cloud-center/api/jsis/upload/downHttpFile?path=" + url + '&name=' + name;
window.open(path);
},
cancleDelete () {
this.isEdit = false
this.$emit('cancelImg')
},
handleRemove (file, fileList) {
console.log('删除', file, fileList);
this.isEdit = true
if (this.fileList.length > 1) {
this.$refs.upload.clearFiles()
this.fileList = []
} else {
// let index =
// this.fileList =
this.fileList = []
}
console.log('existFileList', this.existFileList, this.fileList)
if (!this.fileList.length) {
// this.$nextTick(() => {
// document.querySelector('.el-upload').style.display = 'block'
// })
this.showUploadBtn = true
}
this.$emit('update:fileList', this.fileList)
},
handleExceed(files, fileList) {
this.$message.warning(`当前限制选择 ${this.limit} 张图片，本次选择了 ${files.length} 张图片，共选择了 ${files.length + fileList.length} 张图片`);
},
handleSuccess (response, file, fileList) {
console.log('上传成功', this.$refs.upload.$el)
if (response.respCode == 'success') {
this.fileList.push({
name: file.name|| new Date()-0,
url: response.respData.url,
path:response.respData.path
})
this.isEdit = true
}
this.$emit('update:fileList', this.fileList)
},
handlePictureCardPreview(file) {
this.dialogImageUrl = file.url;
this.dialogVisible = true;
},
beforeAvatarUpload(file) {
console.log('beforeAvatarUpload file', file)
const isJPG = this.acceptImgType.includes(file.type);
const isLt2M = file.size / 1024 / 1024 < 5;
if (!isJPG) {
this.$message.error('不支持此类型!'+'请上传'+this.acceptImgType.join('、')+'等类型文件');
return false
}
if (!isLt2M) {
this.$message.error('上传图片大小不能超过 5MB!');
return false
}
// if (isJPG && isLt2M) {
// this.$message({
// message: `正在上传，请稍等...`,
// duration: 2000,
// type: 'success'
// })
// }
// 这个方法就是去限制上传图片的像素控制
return this.checkImageWH(file, this.supportFileWidth, this.supportFileHeight);
},
// 处理文件上传操作
handleFileUpload(file) {
console.log('action', file)
this.loading = true;
let form = new FormData()
form.append('imgFile', file.file)
form.append('projectCode', this.projectCode)
uploadPicture(form).then(resp => {
console.log('图片上传成功', resp)
if ("success" == resp.respCode) {
this.fileList.push({url: resp.respData})
}
}).catch((e) => {
this.$message.error(e.message);
this.$refs.upload.clearFiles();
})
},
// 配置图片像素
checkImageWH(file, width, height) {
let self = this;
return new Promise(function (resolve, reject) { // 文件读取异步函数变成同步执行
let filereader = new FileReader();
filereader.onload = (e) => {
let src = e.target.result;
const image = new Image();
image.onload = function () {
if (width && this.width !== Number(width)) {
self.$message.warning(
"请上传宽为等于" + width + "像素的图片!"
);
reject();
} else if (height && this.height !== Number(height)) {
self.$message.warning(
"请上传高度等于" + height + "像素的图片!"
);
reject();
} else {
resolve();
}
};
image.onerror = reject;
image.src = src;
};
filereader.readAsDataURL(file);
});
},
clearFiles() {
this.fileList = [];
this.$refs.upload.clearFiles();
},
editParamValue () {
if (!this.fileList.length) {
this.$message.warning('请上传背景图片')
return
}
this.isEdit = false
let data = {...this.imgInfo}
data.paramValue = this.fileList[0].url
this.$emit('updateParamImg', data)
}
},
watch: {
imgInfo:{
deep: true,
handler: function (val, oval) {
console.log('监听图片信息', val)
this.supportFileWidth = val.pictureType.split('x')[0] || val.width
this.supportFileHeight = val.pictureType.split('x')[1] || val.height
this.remark = val.remark
this.existFileList = val.imgUrl
this.fileList = [...this.existFileList]
console.log('this.existFileList', this.existFileList)
this.$nextTick(() => {
if (this.existFileList.length) {
// document.querySelector('.el-upload').style.display = 'none'
} else {
// document.querySelector('.el-upload').style.display = 'block'
this.showUploadBtn = true
}
})
},
immediate: true
},
},
mounted() {
}
}
</script>
<style lang="scss">
.uploadImg {
.is-disabled + .el-upload {
cursor: not-allowed!important;
}
.is-disabled + .el-upload--picture-card:hover,.is-disabled + .el-upload:focus {
border-color: #c0ccda;
color: #c0ccda;
}
}
.uploadImg-globalParams {
display: flex;
justify-content: flex-start;
align-items: center;
.el-upload--picture-card,.el-upload-list__item {
width: 70px;
height: 70px;
line-height: 67px;
}
.icon-check {
padding: 0 10px;
color: #67c23a;
cursor: pointer;
}
}
</style>
<style lang='scss' scoped>
.tips{
color: #F56C6C;line-height: 1.5;
}
.hideUpload /deep/ .el-upload{
display:none;
}
.showUpload /deep/ .el-upload{
display:block;
}
.uploadImg-globalParams ::v-deep .el-upload-list__item {
transition: none !important;
}
</style>
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