What if the Salary is Not Listed?

I enjoy reading your blogs. My job is very boring and is ending soon so I spend most of my time at work reading old post from your blog and trying to figure out my next step in life. I do have one question tho. As I have been applying to jobs, I have noticed one thing. Many HR representatives won’t give out the pay for the jobs that they are calling for me to interview for. Now, I don’t want to waste my time asking off from work and the companies time that I am applying for if the pay is not within my standards. So my questions is do I still go to the interview without knowing the salary upfront?