js operator example code_javascript skills

Copy code The code is as follows:

var $mfunc=function(){
return {
//This function determines the browser type. For simplicity, it returns a numerical representation,
//1.ie6;2.ie7; 3.ie8;4.ie5.5;5, Firefox;6.chrome;7 .Opera;8.Safari;0. Undetectable browser
//Other browsers can add it themselves
whichOS:function(){
var useragent=navigator.userAgent.toLowerCase();
return (/MSIE 6/i.test(useragent)==true&&1)||
(/MSIE 7/i.test(useragent)==true&&2)||
(/MSIE 8/i.test (useragent)==true&&3)||
(/MSIE 5/i.test(useragent)==true&&4)||
(/Firefox/i.test(useragent)==true&&5)||
(/Chrome/i.test(useragent)==true&&6)||
(/Opera/i.test(useragent)==true&&7)||
(/Safari/i.test(useragent)= =true&&8)||0
}
}
}()

Pay attention to the && and ||, the explanations are all in the comments