Improving tooltip performance but now does not work in IE7 or IE6 jquery and inline styles_问答_开发者

Improving tooltip performance but now does not work in IE7 or IE6 jquery and inline styles

开发者 https://www.devze.com 2023-01-15 00:08 出处：网络

I have created a tooltip that appends a DIV with text to the page. I have managed to get it to appear in the position i want and follow the mouse as it moves.

I have created a tooltip that appends a DIV with text to the page.

I have managed to get it to appear in the position i want and follow the mouse as it moves.

I was previously doing this with inline styles and updating the top, left absolute positioning co-ordinates dynamically inline.

This seems to cause performance issues so i wrote the dynamic styling to a <style> in the <head> of the dosument which works fine in Firefox but now not in IE7 or IE6.

The jsFiddle is here;

http://jsfiddle.net/SBhnc/7/

I 开发者_运维技巧guess i need to remove the tag from the on mouseout as well but IE seems to render it once and then always again in the same position.

I would obviously like it to work in all browsers and not suffer any massive performance hits like it was when writing inline styles.

Not sure exactly where to start, so how about my changes? As you can see, it now works just fine in Internet Explorer. Explanations for each change:

Internet Explorer allows a maximum number of StyleSheets (31 or 32, I think) and on your mousemove event you were appending a new <style> element to the head. When it reaches the limit the tooltip never moves again. I switched it back to css() for you.
Every time you mouseover the elements, you attach a new mousemove event. The problem here is that you never unbind this handler, so mouse off, mouse on causes a new handler to be attached each time, doubling the work being done and over-stressing the browser (poor IE!). I moved the mouseover handler to it's own space where it's only created and attached once.
Each mouseover would create the tooltip, then on mouseoff you detach it. Much better to have it in the DOM to start with, just hide() and show() it.
You don't do any caching of selectors or variables. Each time you write $('#tooltip') it's an extra lookup. Save the result of $('#tooltip') to a variable and use the variable.

I did some of the work caching $('#tooltip'), but you should do the same for $(this). mousemove is a fairly stressful event, and can be called many times within a few ms. This causes slowdown on the rendering because it waits for the script to complete.