限制字符个数显示

　　实现此功能的算法有很多，这里记录一个自己使用的：

<!DOCTYPE html>
<html ng-app='myApp'>
    <head>
        <meta charset='utf-8'>
        <script src='angular.js'></script>
        <script src='jquery-1.11.3.js'></script>
    </head>
    <body>
        <div ng-controller='myCtrl'>
            字符串：<input ng-model="inputValue" ng-change='valueChangFnc(inputValue)' placeholder="请输入字符串"><br/>
            字节限制显示：<input ng-model="maxByte" ng-change='byteChangFnc(maxByte)'><br/>
            处理结果：{{message}}
        </div>
        <script>
            angular.module("myApp",[])
            .controller("myCtrl",function($scope){
                $scope.inputValue = "";
                $scope.maxByte = 10;
                $scope.valueChangFnc = function (inputValue){
                    if(inputValue) {
                        $scope.message = getDisplayChars(inputValue, $scope.maxByte);
                    } else {
                        $scope.inputValue = "";                        
                    }
                }
                $scope.byteChangFnc = function (maxByte) {
                    if(maxByte) {
                        $scope.message = getDisplayChars(inputValue, $scope.maxByte);
                    } else {
                        $scope.maxByte = 10;                        
                    }                    
                }
                
                function getDisplayChars(str, maxLength) {
                    //计算字节数
                    var chars = 0;
                    //存储超长时最后一位的下标
                    var sub = '';
                    for (var i = 0; i < str.length; i++) {
                        var code = str.charCodeAt(i);
                        var char = code > 255 ? 2 : 1;
                        chars += char;
                        if (chars > maxLength) {
                            sub = i;
                            break;
                        }
                    }
                    if (sub) {
                        str = (str.slice(0, sub)) + '...'
                    }
                    return str;
                }
            })
        </script>
    </body>
</html>

 

posted @ 2017-10-19 15:16  名字不好起啊  阅读(292)  评论(0)  编辑  收藏  举报