title: Checking value exists, showing error message - before submitting form via jquery
body: <p>Can anyone help with checking if value exists?</p>
  
  <p>I need to check that name, telephone,email and enquiry have a value in the form below before submitting the form when the button is clicked...If there is no value need to display an error message.</p>
  
  <p>This is my form:</p>
  
  <pre><code>&lt;form action="#" id="emailForm" method="post"&gt;
    &lt;div class="left"&gt;
      &lt;input type="hidden" value="1" name="submitted"&gt;
      &lt;input type="text" onblur="if(this.value==''){this.value='name'};" onfocus="if(this.value=='name'){this.value=''};" class="inputField" value="name" name="contactname"&gt;&lt;br&gt;
      &lt;input type="text" onblur="if(this.value==''){this.value='telephone number'};" onfocus="if(this.value=='telephone number'){this.value=''};" class="inputField" value="telephone number" name="telno"&gt;&lt;br&gt;
      &lt;input type="text" onblur="if(this.value==''){this.value='email address'};" onfocus="if(this.value=='email address'){this.value=''};" class="inputField" value="email address" name="email"&gt;&lt;br&gt;
    &lt;/div&gt;
    &lt;div class="right"&gt;
      &lt;textarea rows="10" cols="10" onblur="if(this.value==''){this.value='enquiry'};" onfocus="if(this.value=='enquiry'){this.value=''};" class="textarea" name="enquiry"&gt;enquiry&lt;/textarea&gt;
      &lt;br&gt;
      &lt;button class="send"&gt;&lt;/button&gt;
    &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Any help is much appreciated...</p>