亲写javascript 各类面试题

DOM修改：

1、全文单词首字母大写---2013 腾讯

        var toCapitalize = function (str){
            var aStr1 = str.split(" ");
            var aStr2 = [];
            
            for (var i=0; i<aStr1.length; i++){
                var capitalizeEle = aStr1[i].charAt(0).toUpperCase() + aStr1[i].slice(1);
                aStr2.push(capitalizeEle);
            }
            return aStr2.join(" ");
        }
    
    var str1 = "Your organization has made significant technology investments pport solutions can help you opportunities.";
    alert(toCapitalize(str1))

其实，如果数据不用于后台运算，只是表现上的首字符大写的话，这样就可以了：

#foo{text-transform:capitalize}

算法题：

1、两个字符串A、B ，假设字符串A 长度为m，假设字符串B，长度为n，找出在A中包含的B的所有字符。----2013 腾讯

var aCommonChar = function (a,b){
    var result = [],hashTable = {};
//1 历遍第一个参数字符串，删除掉重复的字符，放入结果hash表中。
    for (var i = 0; i < a.length; i++){
        var name1 = a.charAt(i);
        if (!hashTable[name1]){
            hashTable[name1] = 0;
        }
    }

//2  历遍第二个参数字符串，如果第二个字符串中有和上面hash中的键名相同的字符，则修改键值为1。
    for (var j=0; j<b.length; j++){
        var name2 = b.charAt(j);
        if (hashTable[name2] === 0){
            hashTable[name2] = 1;
        }
    }    
//3 历遍hashTable，把键值为1的键名push进结果数组   
    for (key in hashTable){
        if (hashTable.hasOwnProperty(key) && hashTable[key] === 1){
            result.push(key);
        }
    }        
    return result;    
} 


//test
var A = " The Hebrew word for “wonder” means, “a cause of astonishment.”  God’s dealings with the Psalmist David had been such that people noticed ";
var B = "The disciples were seen as a wonder unto many for basically they were unlearned and ignorant men - Act 4:13. Yet the Apostles felt they were being made a spectacle to the world, 1Co 4:9. ";
alert(aCommonChar(A,B))

 2 写一个RGB色彩值转化为16进制色彩值的函数，例如RGB(0,255,0)→#00ff00

    var sRGBToHex  = function (str){
        if (str.search(/rgb/i) === -1){//兼容ie6-8，它们的颜色值本身就是16进制的
            return str;
        }
        var result = "#";
        str = str.replace(/rgba?((.*))/gi,"$1");
        aStr = str.split(",");
        for (var i=0; i<3; i++){//这里直接写了3，是因为标准浏览器的色彩值可能包含透明度信息，例如RGBA(0,255,30,0.5)
            var iColorAlpha = +aStr[i]; 
            if (iColorAlpha < 16){
                result += "0" + iColorAlpha.toString(16);
            }else{
            result += iColorAlpha.toString(16);
            }        
        }
        return result;
    }