When iterating JSON with Javascript for…in, the final key returned is “remove”
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这确实是一个奇怪的事件。首先，我使用的是Chrome23.x版本，但还没有在其他浏览器中重现。
我从表单的服务器接收到一个JSON数组：
杰森
1 2 3 4 5 6 7 8 9 10 11 | { "layout":0, "caption":"Work History", "cols":[ {"field":"company","label":"Company Name","hidden":false,"order":-1,"validationType":2,"list":[]}, {"field":"date_start","label":"From","hidden":false,"order":-1,"validationType":1,"list":[]}, {"field":"date_end","label":"Until","hidden":false,"order":-1,"validationType":0,"list":[]}, {"field":"position","label":"Title","hidden":false,"order":-1,"validationType":2,"list":[]}, {"field":"description","label":"Description","hidden":false,"order":-1,"validationType":0,"list":[]}, {"field":"project","label":"Project","hidden":false,"order":-1,"validationType":64,"list":[]} ] } |
然后，我尝试用javascript循环Cols对象。"
JavaScript
1 2 3 | for (var c in json.cols) { console.log("col name:" + c); } |
Google Chrome的控制台打印以下内容：
产量
1 2 3 4 5 6 7 | col name: 0 col name: 1 col name: 2 col name: 3 col name: 4 col name: 5 col name: remove |
首先，应该只有6个输出。第二，这个最后的"删除"键是从哪里来的？为什么要列出？
使用
从MDN获取：
If you only want to consider properties attached to the object itself,
and not its prototypes, use getOwnPropertyNames or perform a
hasOwnProperty check (propertyIsEnumerable can also be used).A for...in loop iterates over the properties of an object in an
arbitrary order
JavaScript：
1 2 3 4 5 | for (var c in json.cols) { if( json.cols.hasOwnProperty(c) ) { console.log("col name:" + c); } } |
例子
您的
1 2 3 | for (var i=0; i<json.cols.length; i++) { console.log("col name:" + json.cols[i].label); } |
此外，在您的网页上，似乎有一些脚本与