javascript之input字符串不为空

今天咱们来说如何判断这个java中字符串输入是否为空

------------------------当只有一个input的时候，咱们来进行个判断这个值是否为空------------------------

<div class="form-group">
	<label class="col-sm-2 control-label">标题：</label>
	<div class="col-sm-4">
		<input type="text"  id = "title" class="form-control" placeholder="请输入广告标题（必填，10个字之内）" maxlength="10" name="title" value="${adMaterial.text1}"></div>
	<div  class="col-sm-6 form-control-static"></div>
</div>

<input type="submit" value="提交" class="btn btn-orange" onclick="return checkStr()"></div>

<script>
            function checkStr() {
                var title = document.getElementById("title").value.trim();
                var desc = document.getElementById("desc").value.trim();
                if(title == null || title == ""){
                    alert("标题不能为空");
                    return false;
                }
</script>

　　

 

------------------------当有多个input的时候，咱们来判断这个一系列的值是否为空-----------------------

<div class="form-group">
	<label class="col-sm-2 control-label">标题：</label>
	<div class="col-sm-9">
		<input type="text" class="form-control" placeholder="10字之内,必填" maxlength="10" name="title" value="${one.title}">
	</div>
</div>

<input type="submit" value="提交" class="btn btn-orange" onclick="return checkStr()"></div>

  <script>
	function checkStr(){
		var message = "";
		var titles = document.getElementsByName("title");
		for(var i = 2 ; i < descs.length ;i++){
			var desc = descs[i].value.trim();
			if(desc == null || desc ==""){
				message += "第"+(i - 2)+"个描述不能为空\r\n";
			}
		}
		if(message != ""){
			alert(message);
			return false;
		}
	}
</script>