For example:

td has the width set, span has no width set.

1. Use $.width() to get the integer width, $('td').width() to get the 218px, span is 129px
2. Use clientWidth to get the width without margins and boder , span width is 0, td width is '218'
3. Use getComputedStyle to get final width , accurate to the decimal point , but the width of span obtained is auto, td is 217.5

question:

How to get the exact width of an element with no width set (accurate to the decimal point, displayed in px units)?