Selenium Javascript executor returns null

Question

I have the following JavaScript code returning null when ran through Selenium JavascriptExecutor. However, the same code when ran in Firefox developer console returned a value.

function tmp(){
    var attrb = jQuery(jQuery("[name='q']")[0]).attr('type');
    if(typeof attrb !== 'undefined' && attrb !== false){
        return attrb;
    } else {
        return '';
    }
}

tmp();

The below is my WebDriver code with the JS the same as above:

JavascriptExecutor jsExec = (JavascriptExecutor)driver;
Object inpType = 
       jsExec.executeScript("function tmp(){...}tmp();");
System.out.println("Type: " + inpType);

Above outputs null instead of "text" string. Any ideas?

Answer 1

You should add a return statement to the result you want to return from inside the jsExec.executeScript(...)

Answer 2

The problem is that you execute two statements in executeScript(). The function definition of tmp() and the function call of tmp().

I don't know the details, but the function definition seems to return null.

Since executeScript returns the first value that can be returned, it returns null. If you don't define the function and write the code inline, it will work.

JavascriptExecutor jsExec = (JavascriptExecutor) driver;
Object inpType = jsExec
    .executeScript("var attrb = jQuery(jQuery(\"[name='q']\")[0]).attr('type');"+
            "if(typeof attrb !== 'undefined' && attrb !== false)" +
            "{return attrb;}" +
            "else{return '';}");
System.out.println("-------------- Type: " + inpType);

This should print your expected value.

Edit: Also, your posted code doesn't escape the "" around [name='q']. This ends the string and causes syntax errors.

Answer 3

you need to use return tmp() instead of tmp() in executeScript() method. Find the related reference driver.executeScript() returns NullPointerException for simple javascript