>Tolerance Checker Development Log – 极限偏差查询器开发日志<
最近的主要工作室录入极限偏差数据库，一直都进展的比较顺利，但是今天录入到JS/js公差带的时候遇到了一点问题，JS/js带的极限偏差是±值，一般比较便捷的记法就是±x，但是我以此格式录入的数据库最后查询出来发生了错误，显示如图1。
What I am doing recently is recording data, there was no problem until plus-minus notation display failure came out. When I met the JS/js tolerance zone, numbers are displayed with ‘±’ ahead, which is like ±x. But the plus-minus notation became ‘?’ as Fig.1.
图.1(Fig.1)
目前我猜测的可能是在查询的某个环节出了问题：
I think it must be an error at following stage:
- php excel reader工具不支持正负号；
- 字符集对正负号的支持问题；
- 查询器默认字体或者字体库的支持问题。
- php excel reader does not support plus-minus notation；
- character set does not support plus-minus notation；
- fonts of the checker/page do not support plus-minus notation.
由于这个问题无伤大雅，我暂时用比较简单的办法略过这个问题：用+/-来代替±。
Nevertheless, it is not a serious error and I decide to replace the ‘±’ with ‘+/-‘ temporarily.