index.js

editorCtx.setContents({
  delta: [{
     attributes: {
        'data-custom': "{"id":"7236472931230024","name":"hdsfh"}",
        alt: "@hdsfh",
        class: "atPeople"
     },
     insert: { image: true }
  }]
})

index.less

.atPeople:after { 
  content: attr(alt);
  position: absolute;
  left:0;
  bottom:0;
  width:96%;
  color:red; 
}

index.wxml

<editor></editor>

在开发工具模拟器上会显示正常的内容：

在真机上显示不出来：