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jsÌṩÁËparseInt()ºÍparseFloat()Á½¸öת»»º¯Êý¡£Ç°Õß°Ñֵת»»³ÉÕûÊý£¬ºóÕß°Ñֵת»»³É¸¡µãÊý¡£Ö»ÓжÔStringÀàÐ͵÷ÓÃÕâЩ·½·¨£¬ÕâÁ½¸öº¯Êý²ÅÄÜÕýÈ·ÔËÐУ»¶ÔÆäËûÀàÐÍ·µ»ØµÄ¶¼ÊÇNaN(Not a Number)¡£
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ÀýÈ磬Èç¹ûÒª°Ñ×Ö·û´® "1234blue "ת»»³ÉÕûÊý£¬ÄÇôparseInt()½«·µ»Ø1234£¬ÒòΪµ±Ëü¼ì²âµ½×Ö·ûbʱ£¬¾Í»áÍ£Ö¹¼ì²â¹ý³Ì¡£×Ö·û´®Öаüº¬µÄÊý×Ö×ÖÃæÁ¿»á±»Õýȷת»»ÎªÊý×Ö£¬Òò´Ë×Ö·û´® "0xA "»á±»Õýȷת»»ÎªÊý×Ö10¡£²»¹ý£¬×Ö·û´® "22.5 "½«±»×ª»»³É22£¬ÒòΪ¶ÔÓÚÕûÊýÀ´Ëµ£¬Ð¡ÊýµãÊÇÎÞЧ×Ö·û¡£Ò»Ð©Ê¾ÀýÈçÏ£º
parseInt("1234blue"); //returns 1234
parseInt("0xA"); //returns 10
parseInt("22.5"); //returns 22
parseInt("blue"); //returns NaN
parseInt()·½·¨»¹Óлùģʽ£¬¿ÉÒ԰Ѷþ½øÖÆ¡¢°Ë½øÖÆ¡¢Ê®Áù½øÖÆ»òÆäËûÈκνøÖƵÄ×Ö·û´®×ª»»³ÉÕûÊý¡£»ùÊÇÓÉparseInt()·½·¨µÄµÚ¶þ¸ö²ÎÊýÖ¸¶¨µÄ£¬ËùÒÔÒª½âÎöÊ®Áù½øÖƵÄÖµ£¬ÐèÈçϵ÷ÓÃparseInt()·½·¨£º
parseInt("AF", 16); //returns 175
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parseInt("10", 2); //returns 2
parseInt("10", 8); //returns 8
parseInt("10", 10); //returns 10
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parseInt("010"); //returns 8
parseInt("010", 8); //returns 8
parseInt("010", 10); //returns 10
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When web pages or applications begin to feel slow, analyzing assets as they come over the wire and profiling scripts while they are running allows you to focus your optimization efforts where they are needed most.
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