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title: JavaScript操控光标，你会么？ categories:

• JavaScript
• 杂物间 tags:
• tech
• cnblogs warning: true date: 2013-04-11 05:15:00 fromUrl: http://www.cnblogs.com/hustskyking/archive/2013/04/11/set_and_get_cursor_position.html from: 博客园

var getObj = function ( id ) {
    //获取对象
    var ele = document.getElementById(id);
    //返回结果
    return {
        element: ele,
        startPos: 0,
        endPos: 0,
        init: function(){
            var _this = this;
            if( !("__proto__" in {}) ){
                this.element.attachEvent("onmouseup", _this.getPos);
            }else{
                this.element.addEventListener("mouseup", _this.getPos, false);
            }
            return this;
        },
        getPos: function () {
            var _this = this;
            if( document.selection ) {
                try{
                    var range  = document.selection.createRange();
                    var drange = range.duplicate();
                    drange.moveToElementText( _this.element );
                    drange.setEndPoint( "EndToEnd", range );
                    this.startPos = drange.text.length - range.text.length;
                    this.endPos   = this.startPos + range.text.length;
                }catch(e){

                }
            }else if( window.getSelection ){
                try{
                    this.startPos = this.element.selectionStart;
                    this.endPos   = this.element.selectionEnd;
                }catch(e){
                    //throw new Error("getPos error");
                }
            }
            return this;
        },
        setPos: function ( m, n ) {
            var arg2 = n || m;
            if( document.selection ) {
                var range = document.selection.createRange();
                range.collapse(true);
                range.moveEnd('character', arg2);
                range.moveStart('character', m);
                this.element.focus();
            }else if( window.getSelection ){
                this.startPos = this.element.selectionStart = m;
                this.endPos   = this.element.selectionEnd = arg2;
                this.element.focus();
            }
        },
        getStr: function( m, n ){
            this.getPos( m, n );
            return this.element.value.toString().slice(this.startPos, this.endPos);
        }
    };
};

var t = getObj("box").init();

//选中从m到n之间的内容
t.setPos(m, n);
//一个参数就是设置光标位置
t.setPos(m);

//这个算是一个内置函数，每次选择都自动调用了，可以不管
t.getPos();

//获取选中的字符串
t.getStr();

//执行你送入的函数
function yourFun(){}
//这个方法还没加进去，感觉用处也不大，原理就是使用call
t.invoke(yourFun);