form+iframes模拟文件上传

2 JS部分

//上传文件
//监听frame的 onload方法
let oFrm = document.getElementById("uploadframe");
oFrm.onload = oFrm.onreadystatechange = function () {
    if (this.readyState && this.readyState != "complete") return;
    //获取iframe里面的内容
    let responseText = document.getElementById("uploadframe").contentWindow.document.getElementsByTagName("BODY")[0].innerText;
    //上传完成后的处理
    if (responseText != "") {
 let responseData = JSON.parse(responseText);
 // alert(JSON.parse(responseText));
 $('.update-file .selected-option').show();
 $('.update-file .selected-option ul').html('
+ responseData.RetValue.filePath + '">' + responseData.RetValue.fileName + '
');
    }
}

//监听文件路径变化
$("#fileLocalFile").change(function () {
    let filePath = $("#fileLocalFile").val();
    if (filePath != "") {
 let extionType = filePath.substr(filePath.lastIndexOf(".") + 1);
 if (extionType != "xls" && extionType != 'xlsx' && extionType != 'jpg' && extionType != 'jpeg' && extionType != 'pdf') {
     alert("请上传jpg、pdf、excle等格式，大小1.5M以内的文件");
     $("input[name=fileLocalFile]").val("");
     return;
 } else {
     if ($('.update-file .selected-option ul').html() == '') {
  let index = filePath.lastIndexOf("\"),
      fileName = filePath.substring(index + 1, filePath.length);
  $('#upload')[0].submit();
  $("input[name=fileLocalFile]").val("");
     } else {
  //确认弹层
  $('.yi-mask').show();
  $('#/confirm/iD').show();
     }

 }
    }
});

$('#confirmD .btnok').click(function () {
    $('#/confirm/iD').hide();
    $('.yi-mask').hide();
    let filePath = $("#fileLocalFile").val();
    let index = filePath.lastIndexOf("\"),
 fileName = filePath.substring(index + 1, filePath.length);
    $('#upload')[0].submit();
    $("input[name=fileLocalFile]").val("");
});
//弹层关闭
$('#confirmD .close,#confirmD .btnok').click(function () {
    $('.yi-mask').hide();
    $(this).parents('.yi-modal').hide();
    $("input[name=fileLocalFile]").val("");
})

#upload {
    position: relative;
    float: left;
}

#fileLocalFile {
    opacity: 0;
    filter: alpha(opacity=0);
    position: absolute;
    left: 0;
    top: 0;
    width: 70px;
    height: 30px;
    z-index: 1;
    cursor: pointer;
}

 $("#uploadBtn").click(function() {
  	$("#fileLocalFile").trigger("click");
 });