1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>数据类型转换</title> 6 <script type="text/javascript"> 7 /* 8 var a1=1; 9 var a2=23.45; 10 var a3=-34.1; 11 */ 12 13 //var n1=String(a1); //转化为字符串 14 //var n1=a1.toString(); //转化为字符串 变量.toString 15 //alert(n1); 16 //alert(typeof(n1)); 17 18 /*var b1="123"; 19 var b2="12abc"; 20 var b3="mylove"; 21 */var b4="14期威武" 22 var b6="3.56"; 23 //var b5=Number(b4); 24 //var b5=parseInt(b4) 25 //var b5=parseFloat(b4); 26 27 var c1=123; 28 var c2="345"; 29 var c3; 30 var c4=null; 31 var c5=0; 32 var c6=Infinity; 33 var c7=Boolean(c6); 34 35 36 var d1=12; 37 var d2="3"; 38 var d3=d1-d2; 39 alert(d3); 40 alert(typeof(d3)); //类型自动转换为number类型 41 42 </script> 43 </head> 44 <body> 45 </body> 46 </html>