更改

var reg = /(?:([0-9A-Za-z_])([\u4e00-\u9fa5]))|(?:([\u4e00-\u9fa5])([0-9A-Za-z_]))/g;

var reg = /(?:([0-9A-Za-z_])([\u4e00-\u9fa5]))|(?:([\u4e00-\u9fa5])([0-9A-Za-z_]))/g;

$('.mw-parser-output').textContent = $('.mw-parser-output').textContent.replace(reg, '$1$3 $2$4');

$('.mw-parser-output).each(function () {

   while( match = reg.exec(targetText) !== null ) {

     this = this.replace(reg, "$1$3 $2$4");

});