passing the value of a parameter from java to javascript

[harmeet bawa]

This is what I am doing:

I have a JSP in whhich I display rows for a table (picking the data up from the database). This code for generating the table rows is in a java class. After its displayed, I want to make a select on a row and delete it. What I am tryin to do here is that I am generationg an id and linking that id with each row. This id comes back as a request parameter to the same jsp. I am trying to get the ids value in a javascript fiunction on the jsp. But it dosesn seem to work.

[Bear Bibeault]

What does "it doesn't work" mean? How are you trying to get the value into javascript? Without details it's impossible to even begin to guess what you are trying to do or what the issue may be.

[Scott Selikoff]

To answer the question in your topic (because I don't follow your post) you can 'convert' a JSP variable (lets use a java.lang.String as an example) to a Javascript variable very easily:

var myJavaScriptVariable = <%=myJavaString%>;

Then, anywhere in the javascript, just call myJavaScriptVariable and if the page is finished loading, the variable will be available.

[Saskia de Jong]

Originally posted by Scott Selikoff:

var myJavaScriptVariable = <%=myJavaString%>;

Then, anywhere in the javascript, just call myJavaScriptVariable and if the page is finished loading, the variable will be available.

That's only going to work for very basic value. In general you need to escape you Java variable before assigning its value to the javascript var. Don't forget that the assignment happens by literally printing the Java var's value to the page.

As a starting point you could use the following code:

public static String JavaScriptEscape(String input) {
StringBuffer filtered = new StringBuffer();

for ( char c : input.toCharArray() ) {
switch (c) {
case '\'':
filtered.append("\\'");
break;

case '"':
filtered.append("\\\"");
break;

case '\n': case '\r':
break;

default:
filtered.append(c);
}
}
return filtered.toString();
}

then in your bean, do something like:

 
public getMyStringForJavascript() {
   return JavaScriptEscape(myString);
}

and finally, on the JSP page:

var myJavaScriptVariable = '${myBean.myStringForJavascript}';

of course, for numbers you don't use the single quotes.