Z-index not working with jquery css

Question

How is it that this works:

$("#linechart").css({
      position:'fixed',
      top: "4%",
      left: "2%",
      height: "92%",
      width: "96%"
  });

and this breaks all the javascript:

$("#linechart").css({
      position:'fixed',
      top: "4%",
      left: "2%",
      height: "92%",
      width: "96%",
      z-index: "5"
  });

Answer 1

You have to define like this:

"z-index": "5"

Or uppercase if you don't want to define in quotes:

zIndex: "5"

Answer 2

Try this

$("#linechart").css({
      position:'fixed',
      top: "4%",
      left: "2%",
      height: "92%",
      width: "96%",
      'z-index': "5"
});

and reason is when we use css in jQuery we have to write like this if the word has space in between words

Answer 3

您可以看到以下内容：204行的jQuery Source Code 。

"zIndex": true