可以通过设置“validateBeforeNext”选项来手动触发验证。将其设置为true，即可在“previous”按钮点击之前调用验证函数。代码示例如下：

{
  "type": "wizard",
  "steps": [
    {
      "name": "step1",
      "title": "Step 1",
      "validateBeforeNext": true,
      "fields": [
        {
          "name": "field1",
          "type": "text",
          "label": "Field 1",
          "required": true
        }
      ]
    },
    {
      "name": "step2",
      "title": "Step 2",
      "fields": [
        {
          "name": "field2",
          "type": "text",
          "label": "Field 2",
          "required": true
        }
      ]
    }
  ]
}