Job descriptions targeting web developers are rarely written well. Many describe job requirements that are frighteningly unreasonable. After all, what LAMP developer is also an expert in .NET development, mobile app development, web design, and Hadoop, and has excellent oral and written communication skills? It’s not that developers like that don’t exist, they are just impossible to find… like unicorns.
Employers know this too – most of them, at least. You should still be wary of job descriptions that misuse technical terms or seem out of touch with current trends. If it mentions “DHTML” at all, discard it immediately!
Job descriptions are written to describe more than what the employer actually needs. Even if you only meet half of the job “requirements”, you should still not be discouraged from applying for the job. You might just be the horse that they need.