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Jquery method to determine whether it is empty: 1. Use undefined to determine, the code is [if(C==null||C==undefined||C==""){//code}]; 2. To determine the length, the code is [if(C.length==0){//code}].
The operating environment of this tutorial: windows7 system, jquery3.2.1 version, thinkpad t480 computer.
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##jquery method to determine whether it is empty:
When writing verification, you need to perform verification when the input value is not empty. The code is as followsif($("#email").val()) {
var isEmail = /^([\.a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-])+/;
if(!isEmail.test($("#email").val())){
$('#popContent').text('请您输入正确的邮箱');
$('#popMask').modal('open');
return false;
}
}I also take the opportunity to summarize the method of jquery to determine whether it is empty
var C = $("class name or id").val();
if(C==null||C==undefined||C==""){
//代码
}(2)if(C.length==0){
//代码
}(3)if(C){
//代码
}
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