Question

I have a form built with jquery. I just want to have an empty form with onfocus set so when a user types something the text disappears.

var $myinput2 = js("<input id='CameraName' name='camera_name' size='24' maxlength='36' value='Enter label for camera' onfocus='if(this.value=='Enter label for camera') this.value='';'/>");

I get a syntax error pointing at the “if(this.value==”

I can’t seem to get the quoting right so this will work. Thanks in advance.

Answer 1

You just have to be careful about escaping quotation marks within a string literal if they’re the same type as the whole string literal is enclosed by.

You’re using single-quotes for your html attributes, so within the inline onfocus handler your JS should use double-quotes but because the whole string is in double-quotes you have to escape those double-quotes:

var $myinput2 = js("<input id='CameraName' name='camera_name' size='24' maxlength='36' value='Enter label for camera' onfocus='if(this.value==\"Enter label for camera\") this.value=\"\";'/>");

That is, within your string literal the inline onfocus will look like this:

"... onfocus='if(this.value==\"Enter label for camera\") this.value=\"\";' ..."

Such that the actual value is:

 onfocus='if(this.value=="Enter label for camera") this.value="";'

Note that you wouldn’t have this problem if you didn’t use an inline event handler and instead did something like:

var $myinput2 = js("<input id='CameraName' name='camera_name' size='24' maxlength='36' value='Enter label for camera' />");
$myinput2.focus(function() {
  if(this.value=="Enter label for camera")
     this.value="";
});

(I’m assuming that js is your alias for jQuery.)