JavaScript：检查html p标签是否为空

Question

I have the following in my project:

 function check() { var empt = document.getElementById('xyz1').value; if (empt == "") { alert("Please input a Value"); return false; } else { return true; } } 

 <a href="test.html" role="button" name="weiter" id="weiter" onclick="check();">Go</a> <p id="xyz1"></p> 

Something I am doing wrong. I always get to the page test.html. The check is not working. Is it even possible, to check if ap tag is empty?
Goal is, if there is nothing in the p tag to get an alert and if there is a string or number getting to the linked page test.html I would like to work in pure JavaScript (no jQuery).

Answer 1

It's innerHTML instead of value. Also, check for null.

 function check() { var empt = document.getElementById('xyz1').innerHTML; if (empt == null || empt == "") { alert("Please input a Value"); return false; } else { return true; } } 

 <a href="test.html" role="button" name="weiter" id="weiter" onclick="check();">Go</a> <p id="xyz1"></p> 

Answer 2

  function check() { event.preventDefault(); var empt = document.getElementById('xyz1').innerHTML; if (empt == null || empt == "") { alert("Please input a Value"); return false; } else { return true; } } 

 <a href="test.html" role="button" name="weiter" id="weiter" onclick="check();">Go</a> <p id="xyz1"></p> 

Function must be event prevent default otherwise run href after on click event.

Another Method

onclick="return check()"

  function check() { var empt = document.getElementById('xyz1').innerHTML; if (empt == null || empt == "") { alert("Please input a Value"); return false; } else { return true; } } 

 <a href="test.html" role="button" name="weiter" id="weiter" onclick="return check();">Go</a> <p id="xyz1"></p>