What does 'object has no properties' really mean

[andersond]

Firefox often tells me that one of my objects has no properties; and, I really don't know how to respond.

//code line:
document.getElementById("nearWater").focus();
 
//error message:
document.getElementById("nearWater") has no properties

Can anyone shed some light on what it really wants?

[gits]

basicly it says that:

document.getElementById("nearWater")

doesn't return you what you expect ... probably a null-value because the element doesn't exist or doesn't exist in this context or might not be reday to be retrieved ...

kind regards