Is css property "top" a string or number in javascript?

say I write the following javascript code:

var top = document.getElementById("SOMEDIVID").style.top;

Would the variable "top" end up storing the 开发者_开发知识库top value as a string or as a number? I want it to be a number.

It is a complex value - a number followed by a unit.

If a unit is missing, it is assumed to be pixels (px).

So, all of these are valid:

80px
80
50%
17em

use parseInt() then

var top = parseInt(document.getElementById("SOMEDIVID").style.top);

It would be a string. You can split off the integer with regular expression then a recast.

parseInt(top.match(/^\d+/)[0]); // integer only

This will tell you if it's a string or a number:

var type = typeof( top );

If it's a string, this will give you a number

var number = parseInt( top );