近期在采集一个网站的时候遇到一部分的页面是使用JS代码来填充数据的，代码如下：
<tr>
<td width="150px" class="success">案件级别:</td>
<td colspan="1">
<script>
var s = getDictLabel([{"id":"4191c4842b3842749dd467655f90b1fa","isNewRecord":false,"remarks":"案件级别","createDate":"2016-11-29 15:19:34","updateDate":"2016-11-29 15:19:34","value":"1","label":"一般事件","type":"case_grade","description":"案件级别","sort":1,"parentId":"0"},{"id":"5e24fd12f3384f38ab10898013fe25d7","isNewRecord":false,"createDate":"2016-11-29 15:19:35","updateDate":"2016-11-29 15:19:35","value":"2","label":"紧急事件","type":"case_grade","description":"案件级别","sort":2,"parentId":"0"},{"id":"f793a78eb44c405b9fd007359df09579","isNewRecord":false,"createDate":"2016-11-29 15:19:36","updateDate":"2016-11-29 15:19:36","value":"3","label":"一般重复","type":"case_grade","description":"案件级别","sort":3,"parentId":"0"},{"id":"3f2605e3f6e648f688b79da5f730aedb","isNewRecord":false,"createDate":"2016-11-29 15:19:34","updateDate":"2016-11-29 15:19:34","value":"4","label":"紧急重复","type":"case_grade","description":"案件级别","sort":4,"parentId":"0"}], 1, '', true);
document.write(s);
</script>
</td>
<td width="150px" class="success">受理时间:</td>
<td colspan="1">2018-08-05 13:39:22</td>
</tr>
对上下文的源码进行分析，找到getDictLabel这个JavaScript的函数实现代码如下：
function getDictLabel(data, value, defaultValue){
for (var i=0; i<data.length; i++){
var row = data[i];
if (row.value == value){
return row.label;
}
}
return defaultValue;
}
通过一番了解，可以获取到td标签中间的script对应的JS代码，通过执行JS代码获取对应的数据。找到了一个Python的库pyexecjs可以实现，可以通过如下代码进行安装：
pip install PyExecJS
核心代码如下：
import execjs
def exec_js_function(js):
# 编译JS代码
ctx = execjs.compile("""
function getDictLabel(data, value, defaultValue){
for (var i = 0; i < data.length; i++){
var row = data[i];
if (row.value == value){
return row.label;
}
}
return defaultValue;
}
""")
# 删除一些无关的字符
jscode = js.replace('document.write(s);', '').replace(', true);', ')').replace('var s =', '')
# 执行代码
return ctx.eval(jscode)
更多用法可以从参考链接获取
参考资料
1、官方主页