テスト
上ので文字列変換まわりネックかと、JCT11280とやらを検索して(略)
違うんじゃねーかなーと思いつつsubstring,substrを比較してみる。
<HTML> <HEAD> <TITLE>js tes</TITLE> <SCRIPT Language="JavaScript"> <!-- // --> </SCRIPT> </HEAD> <BODY bgColor="white"> <P> <CENTER> <H2><B>str,string</B></H2> </CENTER> <BR> <HR> <SCRIPT Language="javascript"> <!-- str="abcdefghijkllm12345678900000000000000000000000"; for (i=0; i<10; i++) {str +=str;} str1=""; str2=""; num =500; len=str.length-1; time1=(new Date()).getTime(); for (i=0; i<num; i++) { str1=str1+str.substring(0,len); } time2 =(new Date()).getTime(); for (i=0; i<num; i++) { str2=str2+str.substr(0,len); } time3 =(new Date()).getTime(); ans ="<font color=red>substring</font>"; rate=(time3-time2)/(time2-time1); if( time3-time2>time2-time1) { ans ="<font color=blue>substr</font>"; rate=(time2-time1)/(time3-time2); } txt='substring '+(time2-time1)+'msec<BR>substr ' +(time3-time2)+'msec<BR>str.length '+str.length +'<p>遅いのは'+ans+'...'+Math.round(1000-rate*1000)/10+'%'; document.write(txt); // --> </SCRIPT> <HR> </BODY> </HTML>
結局あまり変わらず。
(あ、ちょいと間違ったかも。)