问题
How to show a javascript 'var' in my jsp?
...
<script type="text/javascript">
... // My code to get the value.
var val = combo.getValue();
</script>
<body>
The value is : //to be displayed here
</body>
回答1:
Add a HTML element which should mark the place where the value is to be displayed and give it an id.
<body>
The value is : <span id="value"></span>
</body>
Then let your JS access it by document.getElementById() and modify its inner HTML.
document.getElementById("value").innerHTML = val;
You only need to ensure that the particular script executes after the HTML page has loaded. Do it during window.onload or put the <script> at end of <body> or wrap it in a function which you execute on some event.
As to the JSP part, this is not relevant here. All JSP does is generating and sending HTML/CSS/JS code from webserver to webbrowser. JavaScript knows nothing about JSP, all it can see and access is HTML/CSS which you can also see by rightclicking the page in webbrowser and choosing View Source.
See also:
- Communication between Java/JSP/JSF and JavaScript
回答2:
You need to place it somewhere so it could be pushed to your JSP page. A hidden field is a good option:
<script type="text/javascript">
... // My code to get the value.
document.getElementById("nn").value = combo.getValue();
... you could submit the form here if you want
</script>
<body>
The value is : //to be displayed here
<form action="yourjsp.jsp" method="get">
<input type="hidden" id="nn"/>
</form>
</body>
Other possibility might be using AJAX.
One way or another, I would suggest you reading a little bit more on general topics about Web Applications to differentiate JSP/JavaScript/POST/GET/CSS/HTML and other basic concepts.
Good luck!
来源：https://stackoverflow.com/questions/4886229/javascript-to-jsp