__javaScript

Also documented in context in the full Functions and Variables reference.

The javaScript function executes a piece of JavaScript (not Java!) code and returns its value

The JMeter Javascript function calls a standalone JavaScript interpreter. Javascript is used as a scripting language, so you can do calculations etc.

Note

javaScript is not the best scripting language for performances in JMeter. If your plan requires a high number of threads it is advised to use __jexl3 or __groovy functions.

For Nashorn Engine, please see Java Platform, Standard Edition Nashorn User’s Guide.

For Rhino engine, please see Mozilla Rhino Overview

The following variables are made available to the script:

• log - the Logger for the function
• ctx - JMeterContext object
• vars - JMeterVariables object
• threadName - String containing the current thread name
• sampler - current Sampler object (if any)
• sampleResult - previous SampleResult object (if any)
• props - JMeterProperties (class java.util.Properties) object

Rhinoscript allows access to static methods via its Packages object. See the Scripting Java documentation. For example one can access the JMeterContextService static methods thus: Java.type("org.apache.jmeter.threads.JMeterContextService").getTotalThreads()

Note

JMeter is not a browser, and does not interpret the JavaScript in downloaded pages.

Name	Required	Description
Expression	Yes	The JavaScript expression to be executed. For example: - new Date() - return the current date and time - Math.floor(Math.random()*(\${maxRandom}+1)) - a random number between 0 and the variable maxRandom - \${minRandom}+Math.floor(Math.random()*(\${maxRandom}-\${minRandom}+1)) - a random number between the variables minRandom and maxRandom - "\${VAR}"=="abcd"
Variable Name	No	A reference name for reusing the value computed by this function.

Note

Remember to include any necessary quotes for text strings and JMeter variables. Also, if the expression has commas, please make sure to escape them. For example in:

\${__javaScript('\${sp}'.slice(7\,99999))}

the comma after 7 is escaped.

Examples:

\${__javaScript(new Date())}

will return Sat Jan 09 2016 16:22:15 GMT+0100 (CET)

\${__javaScript(new Date(),MYDATE)}

will return Sat Jan 09 2016 16:22:15 GMT+0100 (CET) and store it under variable MYDATE

\${__javaScript(Math.floor(Math.random()*(\${maxRandom}+1)),MYRESULT)}

will use maxRandom variable, return a random value between 0 and maxRandom and store it in MYRESULT

\${__javaScript(\${minRandom}+Math.floor(Math.random()*(\${maxRandom}-\${minRandom}+1)),MYRESULT)}

will use maxRandom and minRandom variables, return a random value between maxRandom and minRandom and store it under variable MYRESULT

\${__javaScript("\${VAR}"=="abcd",MYRESULT)}

will compare the value of VAR variable with abcd, return true or false and store the result in MYRESULT

Related

• Functions and Variables Guide
• Regex Extractor Builder
• Full Functions Reference
• Component Reference