您想熟悉
parseInt()和
toString()。
在您的工具箱中有用的是查看变量以找出它是什么类型的
typeof：
<script type="text/javascript"> function printWithType(val) { document.write('<pre>'); document.write(val); document.write(' '); document.writeln(typeof val); document.write('</pre>'); } var a = "1", b = "2", c = "3", result; // Step (1) Concatenate "1", "2", "3" into "123" // - concatenation operator is just "+", as long // as all the items are strings, this works result = a + b + c; printWithType(result); //123 string // - If they were not strings you could do result = a.toString() + b.toString() + c.toString(); printWithType(result); // 123 string // Step (2) Convert "123" into 123 result = parseInt(result,10); printWithType(result); // 123 number // Step (3) Add 123 + 100 = 223 result = result + 100; printWithType(result); // 223 number // Step (4) Convert 223 into "223" result = result.toString(); // printWithType(result); // 223 string // If you concatenate a number with a // blank string, you get a string result = result + ""; printWithType(result); //223 string</script>
