在同一个jsp上从javascript访问java变量
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Accessing java variable from javascript on same jsp
提问by Vge Shi
Is it possible to access a String type variable defined in jsp from a javascript on the same page?
是否可以从同一页面上的 javascript 访问在 jsp 中定义的 String 类型变量？
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1255">
<title>Insert title here</title>
<script type="text/javascript">
foo();
function foo()
{
var value = "<%=myVar%>";
alert(value);
}
</script>
</head>
<body>
<%
String myVar="blabla";
%>
</body>
</html>
In eclipse I am getting an error
在 Eclipse 中我收到一个错误
myVar cannot be resolved to a variable
采纳答案by Luiggi Mendoza
This won't work since you're trying to use an undefined variable. The code is generated like this:
这将不起作用，因为您正在尝试使用未定义的变量。代码是这样生成的：
... = myVar;
//...
String myVar = "blabla";
Doesn't make sense, right? So, in order to make this work you should declare the variable before using it (as always):
没有意义，对吧？因此，为了完成这项工作，您应该在使用变量之前声明它（一如既往）：
<%
String myVar="blabla";
%>
<script type="text/javascript">
foo();
function foo() {
var value = "<%=myVar%>";
alert(value);
}
</script>
Still, usage of scriptlets is extremely discouraged. Assuming you're using JSTLand Expression Language(EL), this can be rewritten to:
尽管如此，非常不鼓励使用scriptlet 。假设您使用的是JSTL和表达式语言(EL)，则可以将其重写为：
<c:set name="myVar" value="blabla" />
<script type="text/javascript">
foo();
function foo() {
var value = "${myVar}";
alert(value);
}
</script>
If your variable has characters like "inside, then this approach will faile. You can escape the result by using <c:out>from JSTL:
如果你的变量有像"inside 这样的字符，那么这种方法将失败。您可以使用<c:out>from JSTL来转义结果：
var value = "<c:out value='${myVar}' />";
More info:
更多信息：
