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[Java教程]JS 判断字串字节数,并截取长度


var matchWords;
        function notifyTextLength() {
            var inputNum = document.getElementById("txtTitle").value.replace(/[^\x00-\xff]/g, "**").length; //得到输入的字节数
            if (inputNum <= 200) {
                matchWords = document.getElementById("txtTitle").value.length;
                document.getElementById("inputedWord").innerHTML = inputNum + "字节," + matchWords + "字符";
                document.getElementById("inputtingWord").innerHTML = (200 - inputNum) + "字母,"+(Math.round(((200-inputNum)/2)-0.5))+"汉字";
            }
            if (inputNum > 200) {
                document.getElementById("txtTitle").value = document.getElementById("txtTitle").value.substring(0, matchWords);

 //如果超过200字节,就截取到200字节

             }
               
        }

 

 

<input id="txtTitle" type="text" runat="server" onpropertychange="notifyTextLength();" />

当前已经输入<span id="inputedWord" ></span> 还可以输入<span id="inputtingWord" ></span>