Ajax Submit problem

I have this code that works ok when search button is pressed, but if one hits the enter button, it does not return any value from the database.

function showDetails(str){
    if (str==""){
        document.getElementById("searchDiv").innerHTML="";
        return;
      }

      if (window.XMLHttpRequest) {
          xmlhttp=new XMLHttpRequest();
    }
      else {
         xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    xmlhttp.onreadystatechange=function(){

  if (xmlhttp.readyState==4 && xmlhttp.status==200){
    document.getElementById("searchDiv").innerHTML=xmlhttp.responseText;
    }
  }
    xmlhttp.open("GET","ajax_details.php?q="+st开发者_如何学运维r,true);
    xmlhttp.send();
   }

Here's how I'm using it in a separate page.

searchField is a text input field in my form.

<button type="button" name="search" onclick="showDetails(searchField.value)">Search</button>

Like I said, it returns data from the server only when the search button is pressed but not when you hit the enter button on the computer keyboard. Is there any way I can make it respond to both?

That's because you haven't bound any event to the pressing of a key. Your event is very clearly labeled onclick. So it responds to a click. Bind it to a keypress, check if that keypress is the enter key, and if so trigger the ajax request.