textarea的验证

Question

如何验证form.ie中的textarea,它不应为空或有任何新行,如果是,则提出警报

   <script>
    function val()
    {
      //ifnewline found or blank raise an alert
    } 
   </script>
   <form>  
   <textarea name = "pt_text" rows = "8" cols = "8" class = "input" WRAP ></textarea>
   <input type=""button" onclick="val();"
    </form>

谢谢

Answer 1

尝试这个：

<textarea id="txt" name = "pt_text" rows = "8" cols = "8" class = "input" WRAP ></textarea>

function val()
{
  if (trimAll(document.getElementById('txt').value) === '')
  {
     alert('Empty !!');
  }
} 

function trimAll(sString)
{
    while (sString.substring(0,1) == ' ')
    {
        sString = sString.substring(1, sString.length);
    }
    while (sString.substring(sString.length-1, sString.length) == ' ')
    {
        sString = sString.substring(0,sString.length-1);
    }
return sString;
}