查看一个简单的jQuery的例子来遍历一个JavaScript数组对象。
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var json = [
{ "id" : "1" , "tagName" : "apple" },
{ "id" : "2" , "tagName" : "orange" },
{ "id" : "3" , "tagName" : "banana" },
{ "id" : "4" , "tagName" : "watermelon" },
{ "id" : "5" , "tagName" : "pineapple" }
];
$.each(json, function (idx, obj) {
alert(obj.tagName);
});
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上面的代码片断工作正常,提示 “apple”, “orange” … 等,如预期一样。
问题: JSON 字符串
下面的例子中,声明了一个JSON字符串(随附单或双引号)直接地。
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var json = '[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},
{"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},
{"id":"5","tagName":"pineapple"}]' ;
$.each(json, function (idx, obj) {
alert(obj.tagName);
});
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在Chrome中,它显示在控制台下面的错误:
Uncaught TypeError: Cannot use 'in' operator to search for '156'
in [{"id":"1","tagName":"apple"}...
解决方案:JSON字符串转换为JavaScript对象。
要修复它,通过标准JSON.parse()或jQuery 的 $.parseJSON 将其转换为JavaScript对象。
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var json = '[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},
{"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},
{"id":"5","tagName":"pineapple"}]' ;
$.each(JSON.parse(json), function (idx, obj) {
alert(obj.tagName);
});
//or
$.each($.parseJSON(json), function (idx, obj) {
alert(obj.tagName);
});
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