How to find an anchor with a button in selenium webdriver?

Question

The following HTML code is for clicking a button

<a href="#">
 <button id="listbtn" class="btn btn-info" type="button" name="listbtn">Create</button>
</a>

Have tried the following locators:

// driver.findElement(By.linkText("Create")).click();
// driver.findElement(By.name("listbtn")).submit();
//driver.findElement(By.id("listbtn")).click();
//driver.findElement(By.className("btn btn-info")).click();
//driver.findElement(By.xpath("//*[@id='listbtn']")).click();
//driver.findElement(By.xpath(("td[class='btn btn-info'][value='Create']"))).click();
//driver.findElement(By.linkText("Cancel")).click();
//WebElement element=driver.findElement(By.xpath("//*[@id='listbtn']"));
//driver.findElement(By.xpath("//a[@href='listbtn']")).click();

But when clicking run, it shows invalid locator -

The following is the error exception Exception in thread "main" org.openqa.selenium.InvalidSelectorException:
The given selector btn btn-info is either invalid or does not result in a WebElement. 
The following error occurred: InvalidSelectorError: Compound class names not permitted
Command duration or timeout: 24 milliseconds For documentation on this error, please visit: 
seleniumhq.org/exceptions/invalid_selector_exception.html

• josh test: <a href="#"> <button id="listbtn" class="btn btn-info" type="button" name="listbtn">Create</button> </a>
• demouser123: Can you update the exception thrown (full stack trace)
• josh test: The following is the error exception Exception in thread "main" org.openqa.selenium.InvalidSelectorException: The given selector btn btn-info is either invalid or does not result in a WebElement. The following error occurred: InvalidSelectorError: Compound class names not permitted Command duration or timeout: 24 milliseconds For documentation on this error, please visit: seleniumhq.org/exceptions/invalid_selector_exception.html

Answer 1

I use CSS selectors, thus it would be

driver.findElement(By.cssSelector("a button[id='listbtn']"));

• josh test: ok .. will try the above selector
• Robben: Let me know if it works or not.
• Julian: You can make it a bit less clunky looking if you use id shorthand: "a button#listbtn". Since ids tend to be unique on a page, chances are you will be able to get away with the css selector "#listbtn" by itself
• Robben: @JulianCleary That's true Julian. I write my selectors that way because I like it spelled out - just a personal preference.
• Michael Durrant: If you prefer a less is more approach see my answer sqa.stackexchange.com/a/27854/8992

Answer 2

The error you get is because compound classes are not permitted inside by.className locators.

The By.id locator should be the best and the fastest option here:

driver.findElement(By.id("listbtn"));

You can also construct a CSS selector:

driver.findElement(By.cssSelector("a button#listbtn"));

Note the use of # shortcut.

Answer 3

I prefer the shorter form

driver.findElement(By.css("a button#listbtn"));