字符串转数字类型

 var n1="1";
        var n2="2.22";
        var n3="123abc";
        var n4="yz99";
        var n1=Number(n1);
        var n2=Number(n2);
        var n3=Number(n3);
        var n4=Number(n4);
        document.write("n1的值是:" + n1+ "<br>" + "n1的类型是:"+typeof(n1) + "<br>");
        document.write("n2的值是:" + n2+ "<br>" + "n2的类型是:"+typeof(n2) + "<br>");
        document.write("n3的值是:" + n3+ "<br>" + "n3的类型是:"+typeof(n3) + "<br>");
        document.write("n4的值是:" + n4+ "<br>" + "n1的类型是:"+typeof(n4) + "<br>");
        /*页面输出结果：
        n1的值是:1
        n1的类型是:number
        n2的值是:2.22
        n2的类型是:number
        n3的值是:NaN
        n3的类型是:number
        n4的值是:NaN
        n1的类型是:number*/

 var n1="1";
        var n2="2.22";
        var n3="123abc";
        var n4="yz99";
        var n5="2.99"
        var n1=parseInt(n1);
        var n2=parseInt(n2);
        var n3=parseInt(n3);
        var n4=parseInt(n4);
        var n5=parseInt(n5);
        document.write("n1的值是:" + n1+ "<br>" + "n1的类型是:"+typeof(n1) + "<br>");
        document.write("n2的值是:" + n2+ "<br>" + "n2的类型是:"+typeof(n2) + "<br>");
        document.write("n3的值是:" + n3+ "<br>" + "n3的类型是:"+typeof(n3) + "<br>");
        document.write("n4的值是:" + n4+ "<br>" + "n4的类型是:"+typeof(n4) + "<br>");
        document.write("n5的值是:" + n5+ "<br>" + "n5的类型是:"+typeof(n5) + "<br>");
        /*页面输出：
        n1的值是:1
        n1的类型是:number
        n2的值是:2
        n2的类型是:number
        n3的值是:123
        n3的类型是:number
        n4的值是:NaN
        n4的类型是:number
        n5的值是:2
        n5的类型是:number*/

　　　　 var n1="1";
        var n2="2.22";
        var n3="123abc";
        var n4="yz99";
        var n5="2.99"
        var n1=parseFloat(n1);
        var n2=parseFloat(n2);
        var n3=parseFloat(n3);
        var n4=parseFloat(n4);
        var n5=parseFloat(n5);
        document.write("n1的值是:" + n1+ "<br>" + "n1的类型是:"+typeof(n1) + "<br>");
        document.write("n2的值是:" + n2+ "<br>" + "n2的类型是:"+typeof(n2) + "<br>");
        document.write("n3的值是:" + n3+ "<br>" + "n3的类型是:"+typeof(n3) + "<br>");
        document.write("n4的值是:" + n4+ "<br>" + "n4的类型是:"+typeof(n4) + "<br>");
        document.write("n5的值是:" + n5+ "<br>" + "n5的类型是:"+typeof(n5) + "<br>");
        /*页面输出结果：
        n1的值是:1
        n1的类型是:number
        n2的值是:2.22
        n2的类型是:number
        n3的值是:123
        n3的类型是:number
        n4的值是:NaN
        n4的类型是:number
        n5的值是:2.99
        n5的类型是:number*/