20151005js3

循环嵌套 ：99乘法表示例

    var s = "";
    s += "<table>";

    for (var i = 1; i < 10; i++) {
        s += "<tr>";
        for (var j = 1; j <= i; j++) {

            s += "<td>" + i + "*" + j + "=" + i * j + "</td>";
        }
        s += "</tr>";
    }
    s += "</table>";
    document.getElementById("dcon").innerHTML = s;

选择排序示例

 var iNum = [34, 19, 11, 109, 3, 56];
        var temp=0;
        for (var i = 0; i <= iNum.length-2; i++) {            for (var j = i + 1; j <=iNum.length - 1; j++) {
                if (iNum[i] > iNum[j]) {
                    temp = iNum[j];
                    iNum[j] = iNum[i];
                    iNum[i] = temp;
                }
            }
        }
        for (var a = 0; a < iNum.length; a++) {

            document.write(iNum[a] + "<br/>");
        }

冒泡排序示例

var iNum = [34, 19, 11, 109, 3, 56];
        var temp=0;
        for (var i = 0; i <= iNum.length-2; i++) {//-2 小于等于等同于小于-1
            for (var j =0; j <=iNum.length-1-i; j++) {//-1为了避免下标越界，-x为了让外循环增加一次，内循环参数与比较的元素个数递减
                if (iNum[j] > iNum[j+1]) {
                    temp = iNum[j];
                    iNum[j] = iNum[j+1];
                    iNum[j+1] = temp;
                }
            }
        }
        for (var a = 0; a < iNum.length; a++) {
  
            document.write(iNum[a] + "<br/>");
        }