HTML compatibility does not declare that the position:fixed location fails in DOCTYPE,IE9 Standard mode, which causes the mask layer to appear at the bottom of the page, FF and Chrome are normal

Problem Description: IE9 standard mode, the old system pages are rarely written doctype, but do not write this declaration, the browser for the document parsing mechanism is different, especially for table and style width, height is 100% layout, and highly adaptive implementation of the program has an impact, do not know can be Baidu first, then do not write, and want to add 1 mask layer effect, generally we mask layer is the use of position absolute positioning to achieve, can write fixed, can also write absolute, set to fixed time, Document does not DOCTYPE, will cause the mask layer appears at the bottom of the document, rather than the effect of absolute positioning, switching to IE9 compatibility mode still does not solve the problem, then had to add doctype, but add the old code in the layout of the page is a variety of 100%, page confusion.

Solution:

1. Trouble, modify the style and layout of all affected pages, if you have time

2. Add doctype first, implement the mask, and then switch to IE9 compatibility mode, the page style will not be garbled.

Unverified issues:

IE8 and low versions have this problem

Conclusion:--

Reference Blog: position:fixed; a problem with no effect under IE9