JavaScript自定义函数判断字符串是否为空

2017-01-29 21:06:32 访问(1792) 赞(0) 踩(0)


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1">
    <title></title>
</head>
<body>
    <h1>
        JavaScript自定义函数判断字符串是否为空</h1>
    输入：<br />
    <textarea name="txt_Input" rows="2" cols="20" id="txt_Input" style="height: 100px;
        width: 99%;">
        slowx
        
        </textarea>
    <br />
    <br />
    <input type="button" id="btn_OK" value="确定" onclick="OkClick()" />
    <br />
    <br />
    输出：<br />
    <textarea name="txt_Output" rows="2" cols="20" id="txt_Output" style="height: 100px;
        width: 99%;"></textarea>
</body>
</html>

<script language="javascript" type="text/javascript">
    function StrTrim(str) {
        // 过滤空格 //
        if (str == null)
            return "";

        return str.replace(/(^\s*)|(\s*$)/g, "");
    }

    function StrIsBlank(str) {
        // 是否为空 //
        if (str == null)
            return true;

        str = str + "";

        str = StrTrim(str);

        if (str == "")
            return true;

        return false;
    }

    function OkClick() {
        var inputCtrl = document.getElementById("txt_Input");
        var outputCtrl = document.getElementById("txt_Output");

        var theValue = inputCtrl.value;
        theValue = StrIsBlank(theValue);

        outputCtrl.value = theValue;
    }
 

</script>