javascript console.log 不适用于 jQuery？
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console.log not working for jQuery?
提问by the tao
Here is my jQuery at the bottom of html page:
这是我在 html 页面底部的 jQuery：
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript">
$(document).ready(function () {
$('#login').click(function() {
var co_id = $('#companies').val();
console.log(co_id);
});
});
</script>
When I type this jQuery into the console, then type co_idit works, but when I run this in browser and choose a company and click the correct button, and I would assume when I type co_idinto chrome browser console, it would show my option value? But it is coming back as:
当我在控制台中输入这个 jQuery 时，然后输入co_id它可以工作，但是当我在浏览器中运行它并选择一家公司并单击正确的按钮时，我会假设当我co_id在 chrome 浏览器控制台中输入时，它会显示我的选项值？但它又回来了：
>co_id
ReferenceError: co_id is not defined
Here is html:
这是html：
<select name="" id="companies">
<option value="--">--</option>
<option value="1">Company</option>
<option value="2">Company2</option>
<option value="3">Company3</option>
<option value="68">Company4</option>
<option value="69">Company5</option>
<option value="70">Company6</option>
</select><input id="login" type="submit" value="Login">
回答by ???? ??????
Don't write code if you set the src attribute.
如果您设置了 src 属性，请不要编写代码。
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript">
</script>
<script type="text/javascript">
$(document).ready(function () {
$('#login').click(function() {
var co_id = $('#companies').val();
console.log(co_id);
});
});
</script>
回答by Rouven We?ling
Your problem is, that the Chrome console is always running in the global scope but co_idis scoped to the closure.
您的问题是，Chrome 控制台始终在全局范围内运行，但co_id仅限于闭包。
To inspect the values you have 3 options:
要检查值，您有 3 个选项：
Declare co_id to be in the global scope. To do this simply remove the
varin front of the variable name and addvar co_idin the global scope. I don't recommend this, inevitably you'll forget to make the scope local again and you'll end up with a lot of global variables. They can be a source of a lot of fun bugs.Change the
console.log()to actually output the variable content like this:console.log(co_id);.The best solution: Set a break point in the function by clicking on the line number in the script pane.
声明 co_id 在全局范围内。为此，只需删除
var变量名前面的 并添加var co_id到全局范围内。我不推荐这样做，不可避免地你会忘记再次将作用域设为本地，最终会得到很多全局变量。它们可能是许多有趣错误的来源。更改
console.log()实际输出变量的内容是这样的：console.log(co_id);。最佳解决方案：通过单击脚本窗格中的行号在函数中设置断点。
