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JavaScript functions

alert(sJavaScriptHello);

</script>

This example uses JSP with the intent of outputting the string

“Hello”

into a JavaScript variable. When

this page gets to the browser, you can view the source:

var sJavaScriptHello = “Hello”;

alert(sJavaScriptHello);

</script>

The output looks correct and the JavaScript functions as expected. But now consider another example:

<% String sJspHeSaidHi = “He said, \”hi.\””; %>

var sJavaScriptHeSaidHi = “<%= sJspHeSaidHi %>”;

alert(sJavaScriptHeSaidHi);

</script>

The output to the browser now becomes this:

var sJavaScriptHeSaidHi = “He said, “hi.””;

alert(sJavaScriptHeSaidHi);

</script>

Do you see the problem? The string that was outputted from the JSP contained quotation marks, which

creates a syntax error in JavaScript. This is the most common mistake made when internationalizing

Web pages that use JavaScript to output strings. You must be aware of quotation marks contained within

strings if the string is to be output into JavaScript code. The best way to deal with this is to replace the

quotation marks in all strings before outputting to JavaScript, such as in the following:

<% String sJspHeSaidHi = “He said, \”hi.\””; %>

var sJavaScriptHeSaidHi = “<%= sJspHeSaidHi.replaceAll(“\\\””, “\\\””) %>”;

alert(sJavaScriptHeSaidHi);

</script>

This example converts all quotation marks to a backslash followed by a quotation mark using the Java

replaceAll()

method. The first argument is a string representation of a regular expression (you’ll

remember that regular expression strings must be double-escaped, so

\”

becomes

\\\”

); the second

argument is identical, although this one is a string and not a regular expression. This effectively changes

this string:

“He said, \”hi.\””

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Chapter 19

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