javascript string.indexOf()字元尋找實現方法

提示：您可以先修改部分代碼再運行

<script language="JavaScript" type="text/javascript">if(!Array.prototype.indexOf){Array.prototype.indexOf=function(elt){var len=this.length;var from=Number(arguments[1])||0;from=(from<0)?Math.ceil(from):Math.floor(from);if(from<0)from+=len;for(;from<len;from++){if(from in this&&this[from]===elt)return from;}return-1;};}var array=[2,5,9];var index=array.indexOf(2);document.writeln("[2, 5, 9].indexOf(2) ：<strong>");document.writeln(index);document.writeln("</strong><br />");index=array.indexOf(7);document.writeln("[2, 5, 9].indexOf(7) ：<strong>");document.writeln(index);document.writeln("</strong><br />");</script> </td> </tr></table>

提示：您可以先修改部分代碼再運行