javascript之input字符串不爲空

今天咱們來說如何判斷這個java中字符串輸入是否爲空

------------------------當只有一個input的時候，咱們來進行個判斷這個值是否爲空------------------------

<div class="form-group">
	<label class="col-sm-2 control-label">標題：</label>
	<div class="col-sm-4">
		<input type="text"  id = "title" class="form-control" placeholder="請輸入廣告標題（必填，10個字之內）" 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("標題不能爲空");
                    return false;
                }
</script>

　　

 

------------------------當有多個input的時候，咱們來判斷這個一系列的值是否爲空-----------------------

<div class="form-group">
	<label class="col-sm-2 control-label">標題：</label>
	<div class="col-sm-9">
		<input type="text" class="form-control" placeholder="10字之內,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)+"個描述不能爲空\r\n";
			}
		}
		if(message != ""){
			alert(message);
			return false;
		}
	}
</script>