Javascript 错误：else if语句中应包含声明或语句 if（shirtWidth>=18和&shirtWidth>29）（shirtLength>29）和（shirtSleeve>8.38）；{ 控制台日志； }否则，如果（衣袖长度>=19和衣袖长度==22）（衣袖长度==29）和（衣袖长度>8.13和衣袖长度=21和衣袖长度==23）（衣袖长度==30）和（衣袖长度>8.38和衣袖长度==8.87）；{ 控制台日志（“L”）； }否则，如果（shirtWidth

更改您的代码，那么您就做错了

if (shirtWidth >= 18 && shirtWidth > 29)  (shirtLength >29) && (shirtSleeve > 8.38); {
    console.log("S");    
    } else if (shirtWidth >= 19 && shirtWidth == 22)  (shirtLength == 29) && (shirtSleeve > 8.13 && shirtSleeve < 8.38); {
    console.log("M");    
    } else if (shirtWidth >= 21 && shirtWidth == 23)  (shirtLength === 30) && (shirtSleeve > 8.38 && shirtSleeve == 8.87); {
    console.log("L");    
    } else if (shirtWidth <22 && shirtWidth == 25)  (shirtLength === 31) && (shirtSleeve < 8.63 && shirtSleeve == 9.62); {
    console.log("XL");    
    } else if (shirtWidth < 24 && shirtWidth == 29)  (shirtLength === 34) && (shirtSleeve < 9.63 && shirtSleeve == 10.12); {
    console.log("2XL");    
    } else if (shirtWidth < 26  && shirtWidth == 23)  (shirtLength === 30) && (shirtSleeve < 10.13 && shirtSleeve ==12.00); {
    console.log("3XL");    
    }

if（（衬衫长度>=18&&shirtWidth>29）| |（衬衫长度>29&&shirtsweeve>8.38））{
控制台日志；
}否则如果（（衬衫长度>=19&&shirtWidth==22）| |（衬衫长度==29&&shirtSleeve>8.13&&shirtSleeve<8.38））{
控制台日志（“M”）；
}否则如果（（衬衫长度>=21&&shirtWidth==23）| |（衬衫长度==30&&shirtSleeve>8.38&&shirtSleeve==8.87））{
控制台日志（“L”）；
}else if（（shirtWidth）您在上一个条件中缺少一个
else if
if ((shirtWidth >= 18 && shirtWidth > 29) || (shirtLength >29 && shirtSleeve > 8.38) ){
      console.log("S");    
} else if( (shirtWidth >= 19 && shirtWidth == 22) || (shirtLength == 29 && shirtSleeve > 8.13 && shirtSleeve < 8.38)){
    console.log("M");    
} else if ((shirtWidth >= 21 && shirtWidth == 23) || (shirtLength === 30 && shirtSleeve > 8.38 && shirtSleeve == 8.87)){
    console.log("L");    
} else if ((shirtWidth <22 && shirtWidth == 25) || (shirtLength === 31 && shirtSleeve < 8.63 && shirtSleeve == 9.62)) {
    console.log("XL");    
} else if ((shirtWidth < 24 && shirtWidth == 29) || (shirtLength === 34 && shirtSleeve < 9.63 && shirtSleeve == 10.12)) {
    console.log("2XL");    
} else if((shirtWidth < 26  && shirtWidth == 23) || (shirtLength === 30 && shirtSleeve < 10.13 && shirtSleeve ==12.00)) {
    console.log("3XL");    
}