Javascript 访问json中的元素
下面是我的JSON树。如何访问给定树和框架中的Javascript 访问json中的元素,javascript,html,json,Javascript,Html,Json,下面是我的JSON树。如何访问给定树和框架中的Typedefinition属性，如果条件为所有Typedefinition。我必须穿过这棵树才能找到 if (typedefinition == "ciu'){//do something} else if(typedef == Tank ) else if( hostport) else if( fieldport) 并为每个if做些事情。我必须穿过这棵树，创造一个这样的条件 { "Resp_Data": {
Typedefinitionif (typedefinition == "ciu'){//do something}
else if(typedef == Tank )
else if( hostport)
else if( fieldport)
{
"Resp_Data":
{
"SiteElements":
[
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge00",
"ID": "1"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2003",
"Index": "1",
"Value": "00"
},
{
"EntityId": "2006",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2004",
"Index": "1",
"Value": "B"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
},
{
"EntityId": "9007",
"Index": "1",
"Value": "1"
},
{
"EntityId": "9703",
"Index": "1",
"Value": "0"
}
],
"Connections":
[
{
"SourceElementID": "2",
"DestinationElementID": "1"
}
]
},
{
"SiteElementDef":
[
{
"SiteElementName": "Tank1",
"ID": "2"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "TANK",
"ID": "3"
}
],
"Entities": "",
"Connections":
[
{
"SourceElementID": "5",
"DestinationElementID": "2"
},
{
"SourceElementID": "2",
"DestinationElementID": "1"
}
]
},
{
"SiteElementDef":
[
{
"SiteElementName": "CIU1",
"ID": "3"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "CIU",
"ID": "4"
}
],
"Entities":
[
{
"EntityId": "7050",
"Index": "1",
"Value": "2"
},
{
"EntityId": "9006",
"Index": "1",
"Value": "1"
},
{
"EntityId": "7050",
"Index": "2",
"Value": "8"
},
{
"EntityId": "7050",
"Index": "3",
"Value": "7"
},
{
"EntityId": "3037",
"Index": "1",
"Value": "1"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "\/dev\/ttyS1",
"ID": "4"
},
{
"Parent": "CIU1",
"ID": "3"
},
{
"TypeDefinition": "HOSTPORT",
"ID": "5"
}
],
"Entities":
[
{
"EntityId": "5022",
"Index": "1",
"Value": "9600"
},
{
"EntityId": "5027",
"Index": "1",
"Value": "3"
},
{
"EntityId": "5020",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5024",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5034",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5025",
"Index": "1",
"Value": "2"
},
{
"EntityId": "5019",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5006",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5012",
"Index": "1",
"Value": "3302"
},
{
"EntityId": "5012",
"Index": "2",
"Value": "2801"
},
{
"EntityId": "5013",
"Index": "1",
"Value": "10000"
},
{
"EntityId": "5013",
"Index": "2",
"Value": "100"
},
{
"EntityId": "5014",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5014",
"Index": "2",
"Value": "30000"
},
{
"EntityId": "5006",
"Index": "2",
"Value": "1"
},
{
"EntityId": "5006",
"Index": "3",
"Value": "2"
},
{
"EntityId": "5005",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5007",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5009",
"Index": "1",
"Value": "3"
},
{
"EntityId": "5008",
"Index": "1",
"Value": "4"
},
{
"EntityId": "5011",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5011",
"Index": "2",
"Value": "2"
},
{
"EntityId": "9015",
"Index": "1",
"Value": "1"
},
{
"EntityId": "9016",
"Index": "1",
"Value": "1"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "\/dev\/ttyS0",
"ID": "5"
},
{
"Parent": "CIU1",
"ID": "3"
},
{
"TypeDefinition": "FIELDPORT",
"ID": "6"
}
],
"Entities":
[
{
"EntityId": "3504",
"Index": "1",
"Value": "40"
},
{
"EntityId": "3507",
"Index": "1",
"Value": "9000"
},
{
"EntityId": "3510",
"Index": "1",
"Value": "2"
},
{
"EntityId": "9011",
"Index": "1",
"Value": "7"
},
{
"EntityId": "9012",
"Index": "1",
"Value": "CIU1"
},
{
"EntityId": "3501",
"Index": "1",
"Value": "4"
},
{
"EntityId": "3502",
"Index": "1",
"Value": "0"
},
{
"EntityId": "3503",
"Index": "1",
"Value": "2"
},
{
"EntityId": "3505",
"Index": "1",
"Value": "0"
},
{
"EntityId": "3500",
"Index": "1",
"Value": "BPM-GPU"
},
{
"EntityId": "9013",
"Index": "1",
"Value": "3"
}
],
"Connections":
[
{
"SourceElementID": "5",
"DestinationElementID": "2"
}
]
},
{
"SiteElementDef":
[
{
"SiteElementName": "CIU2",
"ID": "6"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "CIU",
"ID": "4"
}
],
"Entities": "",
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Tank2",
"ID": "7"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "TANK",
"ID": "3"
}
],
"Entities": "",
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Tank3",
"ID": "8"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "TANK",
"ID": "3"
}
],
"Entities": "",
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge11",
"ID": "9"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2011",
"Index": "1",
"Value": "11"
},
{
"EntityId": "2012",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2013",
"Index": "1",
"Value": "C"
},
{
"EntityId": "9008",
"Index": "1",
"Value": "0"
},
{
"EntityId": "2016",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge22",
"ID": "10"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2003",
"Index": "1",
"Value": "22"
},
{
"EntityId": "2004",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2006",
"Index": "1",
"Value": "B"
},
{
"EntityId": "9007",
"Index": "1",
"Value": "1"
},
{
"EntityId": "9703",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge33",
"ID": "11"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2011",
"Index": "1",
"Value": "33"
},
{
"EntityId": "2012",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2013",
"Index": "1",
"Value": "C"
},
{
"EntityId": "9008",
"Index": "1",
"Value": "0"
},
{
"EntityId": "2016",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge44",
"ID": "12"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2011",
"Index": "1",
"Value": "44"
},
{
"EntityId": "2012",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2013",
"Index": "1",
"Value": "C"
},
{
"EntityId": "9008",
"Index": "1",
"Value": "0"
},
{
"EntityId": "2016",
"Index": "1",
"Value": "1"
},
{
"EntityId": "2003",
"Index": "1",
"Value": "44"
},
{
"EntityId": "2004",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2006",
"Index": "1",
"Value": "B"
},
{
"EntityId": "9007",
"Index": "1",
"Value": "1"
},
{
"EntityId": "9703",
"Index": "1",
"Value": "0"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "Gauge55",
"ID": "13"
},
{
"Parent": "",
"ID": ""
},
{
"TypeDefinition": "GAUGE",
"ID": "2"
}
],
"Entities":
[
{
"EntityId": "2011",
"Index": "1",
"Value": "55"
},
{
"EntityId": "2012",
"Index": "1",
"Value": "B"
},
{
"EntityId": "2013",
"Index": "1",
"Value": "C"
},
{
"EntityId": "9008",
"Index": "1",
"Value": "0"
},
{
"EntityId": "2016",
"Index": "1",
"Value": "1"
},
{
"EntityId": "5",
"Index": "1",
"Value": "54"
}
],
"Connections": ""
},
{
"SiteElementDef":
[
{
"SiteElementName": "\/dev\/ttyS1",
"ID": "14"
},
{
"Parent": "CIU1",
"ID": "3"
},
{
"TypeDefinition": "FIELDPORT",
"ID": "6"
}
],
"Entities":
[
{
"EntityId": "3501",
"Index": "1",
"Value": "4"
},
{
"EntityId": "9011",
"Index": "1",
"Value": "7"
},
{
"EntityId": "3503",
"Index": "1",
"Value": "2"
},
{
"EntityId": "3502",
"Index": "1",
"Value": "0"
},
{
"EntityId": "3505",
"Index": "1",
"Value": "0"
},
{
"EntityId": "9012",
"Index": "1",
"Value": "CIU1"
},
{
"EntityId": "9013",
"Index": "1",
"Value": "2"
},
{
"EntityId": "3504",
"Index": "1",
"Value": "40"
},
{
"EntityId": "3507",
"Index": "1",
"Value": "9000"
},
{
"EntityId": "3510",
"Index": "1",
"Value": "2"
}
],
"Connections": ""
}
]
}
}
var result=myJSONObject.Resp_Data.SiteElements[0].SiteElementDef[0].TypeDefinition
if (!obj.TypeDefinition) {
// ..
}
else if (obj.TypeDefinition == "GAUGE") {
// ..
} // ...
我从结尾剪下了一些元素，使文章符合30000个字符的限制，并使用了正确的代码格式。我认为它们与这个问题无关。你可以。没有帮助吗？你喃喃自语它帮助我得到了“Microsoft JScript运行时错误：'Resp_Data.SiteElements'为null或不是对象”一个错误。现在我的要求已更改，我可以从json访问typedef元素，而无需对其进行分析“无需对其进行分析”？为什么？如果这是您得到的错误，那么您的数据结构与您发布的不一样。无论如何，这个问题太本地化了。如何访问数组和对象是JS的基本知识。看看我之前评论中的链接，或许可以阅读。您需要解决方案的速度不是我们关心的问题，我们是自愿这样做的，我们没有得到报酬。我收到了一个类似Resp_Data的错误。SiteElements[0]。SiteElementDef为null或不是Objects，那么我认为最好通过拆分来完成。试试这个，告诉我你得到数组响应数据了吗。SiteElements[0]是的，我尝试过这个…同样的错误，我得到了…你能给我推荐一个完美的代码吗..请告诉我我非常需要它..myJSONObject.Resp_Data.SiteElements[0]。SiteElementDef这也不起作用吗？我的代码类似于这个函数callme（）{var Data=[{json tree}]//我现在在这里做什么来访问typedef和帧条件//函数callme（）{var data=[{json tree}]；//我现在在这里做什么来访问typedef和帧条件//我提到的上面的json树您的json是一个obj，所以让我们称它为
objobj.Resp_data.sitelements[0].sitelementdef[2]TypeDefinition==“GAUGE”true