上传预览图片自己做的.md

1.无插件预览(window.URL.createObjectURL)

```javascript

//demo 图片预览  单个

$(".demo input#demo_file").on("change",function(){

    var val_1 = $(this).val();

    var valImg = window.URL.createObjectURL(document.getElementById("demo_file").files[0]);//成功预览该图片

    $(".demo div img").attr("src",valImg);

});

 

 

2.多个预览 上传

//得支持同时上传多个

$(".imgButton_w").on("click",function(){

    console.log(1);

    var $input = "<input type='file' id='img_' name='file' class='files'>";

    $("#input_files").append($input);

    $("#input_files input:last-child").trigger("click").siblings().removeAttr("id");

});

var imgArr = [];

function addFunc(){

    var val_ = $("#input_files input:last-child").val();

    var newVal = val_.split(".");

    var reg_ = /^(jpg|png|jpeg|gif)$/;

    if(val_!==''&&!reg_.test(newVal[newVal.length-1])) {

        alert("请上传后缀为jpg、png、jpeg、gif的图片！");

        return false;

    }

    var valImg = window.URL.createObjectURL(document.getElementById("img_").files[0]);//成功预览该图片

    imgArr.push(valImg);

    var $html = '<div class="upload_append_list"><p>' +

        '<a href="javascript:" class="upload_delete delete" title="删除" data-index="">删除</a><br />' +

        '<img id="uploadImage_" src="' + valImg + '" class="upload_image" /></p>' +

        '<span id="img" class="upload_progress"></span>' +

        '</div>';

    $("#preview").append($html);

}

//创建数组存储图片信息  最多9张图，

function max_nine(){

    var length_ = $(".show_img > div").size();

    console.log("length_:"+length_);

    if(length_ >=9){

        alert("最多只能上传9张图！");

    }else{

        addFunc();

    }

}

$(".upload_img ").on("click",function(){

    max_nine();

});

//移除预览但未上传给后台的图片

$(document).on("click","#preview p a.delete",function() {

    var i = $(this).parent().parent().index();

    $("#input_files input").eq(i).remove();

    $(this).parent().parent().remove();//alert("删除预览");

});

function uploadFunc(){

    $("#imgForm").ajaxSubmit({

        type: "post",

        url: "/investManage/financing/addImg.do",

        data: {"projectId":localStorage.projectId},

        dataType: "json",

        success: function (obj) {

            if (obj.login && obj.status == 1) {

                //alert("上传图片成功！");

            } else if (obj.login == false) {

                alert(obj.msg);

                window.location.href = "login.html";

            } else {

                alert(obj.msg);

            }

        },

        error: function () {

            alert("服务器错误，上传图片失败！");

        }

    });

}

```