<p>查看一个简单的jQuery的例子来遍历一个JavaScript数组对象。</p><pre class="brush:js;toolbar:false">varjson=[
{"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);
});</pre><p>上面的代码片断工作正常，提示 "apple", "orange" … 等，如预期一样。</p><p>问题: JSON 字符串</p><p>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。</p><pre class="brush:js;toolbar:false">varjson='[{"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);
});</pre><p><br/></p><p>在Chrome中，它显示在控制台下面的错误：</p><pre class="brush:js;toolbar:false">UncaughtTypeError:Cannotuse'in'operatortosearchfor'156'
in[{"id":"1","tagName":"apple"}...</pre><p>解决方案：JSON字符串转换为JavaScript对象。</p><p>要修复它，通过标准JSON.parse()或jQuery 的 $.parseJSON 将其转换为JavaScript对象。</p><pre class="brush:js;toolbar:false">varjson='[{"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);
});</pre>