<HTML>
<BODY>
<TABLE>
<TR>
<TD>
<LABEL onclick="alert(this.offsetWidth)">1234567890</LABEL>
</TD>
</TR>
<TABLE>
</BODY>
</HTML>
<BODY>
<TABLE>
<TR>
<TD>
<LABEL onclick="alert(this.offsetWidth)">1234567890</LABEL>
</TD>
</TR>
<TABLE>
</BODY>
</HTML>
<BODY>
<TABLE>
<TR>
<TD>
<LABEL onclick="alert(this.offsetWidth)">12345678<br>90</LABEL>
</TD>
</TR>
<TABLE>
</BODY>
</HTML>
<BODY>
<TABLE>
<TR>
<TD width=50>
<LABEL onclick="alert(this.offsetWidth)">12345678<br>90</LABEL>
</TD>
</TR>
<TABLE>
</BODY>
</HTML>得到的不是现在了吗?你是要原来在一行的时候的宽度?
<script language="javascript">
function getLength(obj){
oSpan = document.createElement("SPAN");
oSpan.style.visibility = "hidden";
oSpan.innerHTML = obj.innerText;
document.body.insertBefore(oSpan);
var len = oSpan.offsetWidth;
oSpan.removeNode(true);
return len;
}
</script>
<BODY>
<TABLE>
<TR>
<TD width=50 style="word-break:break-all">
<LABEL onclick="alert(getLength(this))">1234567890</LABEL>
</TD>
</TR>
</TABLE>
</BODY>
</HTML>